Principles and techniques for mental health clinicians

Due  Thursday Sept 12  by 9pm Central Standard U.S.

Before moving through diagnostic decision making, a social worker needs to conduct an interview that builds on a biopsychosocial assessment. New parts are added that clarify the timing, nature, and sequence of symptoms in the diagnostic interview. The Mental Status Exam (MSE) is a part of that process. The MSE is designed to systematically help diagnosticians recognize patterns or syndromes of a person’s cognitive functioning. It includes very particular, direct observations about affect and other signs of which the client might not be directly aware. When the diagnostic interview is complete, the diagnostician has far more detail about the fluctuations and history of symptoms the patient self-reports, along with the direct observations of the MSE. This combination greatly improves the chances of accurate diagnosis. Conducting the MSE and other special diagnostic elements in a structured but client-sensitive manner supports that goal. In this Assignment,

EXAMPLE ONLY

 

CASE PRESENTATION – F

 

INTAKE DATE: May 2014

 

IDENTIFYING/DEMOGRAPHIC DATA:

This is a voluntary admission for this 32 year old Black male. This is F’s first psychiatric hospitalization. F has been married for 13 years and has been separated from his wife for the past three months. He has currently been with his sister. His family residence is in Miami, Fl., where his wife, two daughters and son reside. F has had a 12th grade education plus education to complete an LPN program. In the past, F worked for seven years as an LPN. For the past three years F has been employed at a local print shop. Religious affiliation is agnostic.

 

CHIEF COMPLAINT/PRESENTING PROBLEM:

“I need to learn to deal with losing my wife and children.”

 

HISTORY OF PRESENT ILLNESS:

This admission was precipitated by F’s increased depression with passive suicidal ideation in the past three months prior to admission. He identifies a major stressor of his wife and three children leaving him three months prior to admission. F has had a past history of alcohol binges and these binges are intensified when there is a need for coping mechanisms in times of stress. F was starting vacation from work just prior to admission and recognized that if he did not come to the hospital for treatment of depression and alcoholism, he would expect to have a serious alcohol binge. F reports that in the past three months since separating from his wife, he has experienced sad mood, fearfulness, and passive suicidal ideation. He denies specific suicidal plan. Wife reports that during these past three months prior to admission, F made a verbal suicidal threat.

F reports he has been increasingly withdrawn/non-communicative. His motivation has decreased and he finds himself “sitting around and not interested in doing chores at home”. He reports decreased concentration at work and increased distractibility. F has experienced increased irritability, decreased self esteem, and feelings of guilt/self blame. There is no change in appetite, but F reports an intentional weight loss of 20 pounds since 5 months ago with dieting. F states for many years he doesn’t sleep, having a past history of working double shifts when requested. F reports his normal sleep pattern for many years has been generally three hours of unbroken sleep. F reports past history of euphoria, although wife reports to intake worker observing periods when F’s mood is elevated, and then in the next few hours, F appears out of control with poor impulse control, increased arguing, temper tantrums and alleged shoving and pushing her and the children. He then feels tired and ends up sleeping more than his average pattern.  Wife reports he has not been violent with her since they have been separated.

F denies suicidal ideation at the present time while on the evaluation unit.

 

PAST PSYCHIATRIC HISTORY:

F was seen on an outpatient basis by Dr. S, for a period of two months prior to admission. He was being seen for individual counseling because of the marital problems and depression. Dr. S recently referred F for inpatient rehabilitation.

 

SUBSTANCE USE HISTORY:

F reports a history of some alcohol binges in the past. He began drinking beer in 1999.  When he turned 21 years old, F reports that until two years prior to admission, his pattern of drinking was to get drunk with his social group approximately twice per month. He denies a history of blackouts. He admits to the alcohol binges and heavy use of cocaine (snorting and freebasing on weekends) for a period of three months in 2010. F has received a charge of driving while intoxicated in 3/02 and had lost his driver’s license for six months. Since his marital breakup, F reports using alcohol as a coping mechanism for stress (reporting that he will only drink on weekends now).

 

 

PAST MEDICAL HISTORY:

F reports having been involved in a motor vehicle accident with loss of consciousness in 1991. He states he has no memory of the accident. In 1993, F sustained a head injury when he hit his head on a coffee table. F had a past history of fractured toes with pins being inserted in the third and fourth digits in his right foot after an accident in which he crushed his foot at work. F denies a past history of seizures.

F has had a weight loss of approximately 20 pounds secondary to dieting since 1/99. F smokes approximately two packs of cigarettes per day. F is allergic to Codeine.

 

FAMILY MEDICAL AND PSYCHIATRIC HISTORY:

Father and grandfather have a history of cardiovascular disease.

     F reports that while growing up his parents maintained a satisfactory relationship. Father reportedly worked nights and slept during the day. F did not have much contact with his father but now enjoys a close relationship with his father. He states he has always had his parents support.

During F’s school years, he reports he was an underachiever in elementary school. He denies having had a history of discipline problems or hyperactivity. He states he did well in high school and earned grades of A’s and B’s. F played football in HS. In his senior year of high school, F began using marijuana and alcohol during the spring term. After completing high school, F earned his license as a practical nurse. He states he graduated at the top of his class from nursing school.

F worked as and LPN for approximately seven years. For the past three years he has been employed as a machine operator for a local printer.

F was married for 13 years and has recently been separated for the past three months. F and his wife have three children including a daughter, age 12, a daughter, age 8, and a son age 7. F states he feels very invested as a parent and feels close to his children.

Leisure time activities F has enjoyed in the past include playing softball, skiing, reading, playing poker, and watching football.  His wife has complained that he is doing less of that now since he is drinking more.  F states he has several close friends.

 

CURRENT FAMILY ISSUES AND DYNAMICS (OPTIONAL):

Wife reports that F’s difficulties began to get worse a few months ago when she decided to move out of the house due to F’s increasing erratic behavior. She moved into her parents’ house and F is living with his sister. Wife states that F has been suffering from mood swings where he is “very up” and feeling great, firm in his direction and then within the next few hours, he is often out of control, arguing, throwing temper tantrums, pushing and shoving, and becoming verbally abusive.

Wife states that F has been drinking for several years in the amount of a 12 pack of beer per day plus shots of hard liquor. Although F reported he has been using cocaine on and off for about two years, wife states she does not think that F is presently using cocaine. At one point, after threats from his wife, F told her that he had gone to a clinic for outpatient rehabilitation, but she did not believe him.

Wife describes F as “extremely depressed” now and says F states, “life is over…I wish I was dead…don’t send the kids over to visit because I don’t want them to find my dead body…everything I tough turns to garbage. Wife adds that F suffers from poor self esteem, lack of sleep and an extremely boastful attitude. On the positive side he is a good father, compassionate, creative, and could be an outstanding person.

Wife reports F always had a bad relationship with his mother. F is close to his father who is reported to have an alcohol problem and was allegedly loud and intimidating.

F is currently employed by his wife’s father. F states he has financial problems now due to paying for counseling and child support.

 

MENTAL STATUS EXAM:

(Include the nine areas to the best of your ability)

F presents as a casually dressed male who appears his stated age of 32. Posture is relaxed. Facial expressions are appropriate to thought content. Motor activity is appropriate. Speech is clear and there are no speech impediments noted. Thoughts are logical and organized. There is no evidence of delusions or hallucinations. F denies any hallucinations. F admits to a recent history of passive suicidal ideation without a plan, but denies suicidal or homicidal ideation at the present time. F admits to a history of decreased need for sleep but denies euphoric episodes. His wife has observed a history of notable mood swings. No manic-like symptoms are observed at the time of this examination.

On formal mental status examination, F is found to be oriented to three spheres. Fund of knowledge is appropriate to educational level. Recent and remote memory appear intact. F was able to calculate serial 7’s. In response to three wishes, F replied “I wish that my marriage would work out and that my kids would be happy and that someone would give me a million dollars.

you take on the role of a social worker conducting an MSE.

To prepare:

Videos

Watch the video describing an MSE. Then watch the Sommers-Flanagan (2014) “Mental Status Exam” video clip. Make sure to take notes on the nine domains of the interview.

Youtube Link to video of case  of Sommers-Flanagan (2014) is below 

Sommers-Flanagan, J., & Sommers-Flanagan, R. (Producers). (2014). Clinical interviewing: Intake, assessment and therapeutic alliance [Video file]. Retrieved from

MedLecturesMadeEasy. (2017, May 29). Mental status exam [Video file]. Retrieved from https://youtu.be/RdmG739KFF8 

Require Readings

Morrison, J. (2014). Diagnosis made easier: Principles and techniques for mental health clinicians (2nd ed.). New York, NY: Guilford Press.

Chapter 10, “Diagnosis and the Mental Status Exam” (pp. 119–126)

Chapter 17, “Beyond Diagnosis: Compliance, Suicide, Violence” (pp. 271–280)

American Psychiatric Association. (2013b). Assessment measures. In Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA: Author. doi:10.1176/appi.books.9780890425596.AssessmentMeasures

NoteFocus on the “Cross-Cutting Symptom Measures” section.

· Review the Morrison (2014) reading on the elements of a diagnostic interview.

· Review the 9 Areas to evaluate for a Mental Status Exam and Review the example diagnostic summary write-up provided in attached document

Assignment

Write up a Diagnostic Summary like the diagnostic summary example, include the Mental Status Exam for Carl based upon his interview with Dr. Sommers-Flanagan.

Write a 2 to 3-page case presentation paper in which you complete both parts outlined below:

Part I: Diagnostic Summary and MSE

Provide a diagnostic summary of the client, Carl. Within this summary include:

· Identifying Data/Client demographics

· Chief complaint/Presenting Problem

· Present illness

· Past psychiatric illness

· Substance use history

· Past medical history

· Family history

· Mental Status Exam (Be professional and concise for all nine areas)

o Appearance

o Behavior or psychomotor activity

o Attitudes toward the interviewer or examiner

o Affect and mood

o Speech and thought

o Perceptual disturbances

o Orientation and consciousness

o Memory and intelligence

o Reliability, judgment, and insight

Part II: Analysis of MSE

After completing Part I of the Assignment, provide an analysis and demonstrate critical thought (supported by references) in your response to the following:

· Identify any areas in your MSE that require follow-up data collection.

· Explain how using the cross-cutting measure would add to the information gathered.

· Do Carl’s answers add to your ability to diagnose him in any specific way? Why or why not?

· Would you discuss a possible diagnosis with Carl at time point in time? Why?

Bargaining Strategy in Major League Baseball

Instructions

Analyzing a Case Study

Bargaining Strategy in Major League Baseball

Review Case 4: Strategy in Major League Baseball from the textbook, Negotiation: Readings, Exercises, and Cases. After reading the case, address the following prompts:

  • Assess the issues of conflict between the players and management during the history of the sport.
  • Analyze mistakes made in negotiations and the effect of mistakes on the processes and outcomes of negotiations.
  • Evaluate the interests and goals of each of the parties.
  • Analyze the best solution and strategy for all parties involved, including each party’s best alternative to a negotiated agreement (BATNA).

Submission Details:

  • Submit your answers in a 3 page 

Case 4 Bargaining Strategy in Major League Baseball

Introduction During the winter of 2005–2006, Donald Fehr was faced with some monumental decisions. As the head of the Major League Baseball Players Association (MLBPA), he had been arduously preparing for the upcoming round of negotiations between his union and the owners of the 30 major league baseball clubs (collectively known as Major League Baseball, or MLB). Being the representative of the labor force in a multi-billion dollar business was no easy task, even for a seasoned negotiating veteran. The health—even the very survival—of his union had hung in the balance each time a new basic agreement (the uniform contract between the two sides) was negotiated, and Fehr couldn’t help but remember past work stoppages, which hurt both sides tremendously. Fehr knew that hard bargaining with the ownership group might cause another strike or lockout, but with attendance levels at the highest they had ever been in the history of the sport, he needed to gauge his constituents’ (and his opposition’s) resolve to decide how to approach the process. History The Early Years Tumultuous labor relations in professional baseball were almost as old as the sport itself. What started as a “gentlemen’s game” in the mid-1800’s quickly turned into business when the general public started taking interest in the sport. Throughout the second half of the 19th century, different leagues were formed by American industrialists whose intentions were to capitalize financially on the sport’s growing popularity. Only two leagues stood the test of time, the National League, formed in 1875, and the American League, formed in 1901. In 1903 the two leagues merged to become Major League Baseball, which quickly became the most profitable sports business in America. When players began to realize that their unique skills could be marketed to the highest bidder, nervous owners began to seek ways to ensure that their moneymakers would not jump ship. In the most controversial move in baseball’s early history, the “reserve clause” was developed and implemented into player contracts. In a move that some considered a form of outright collusion, owners agreed amongst themselves that after each season, each club was able to “reserve” five players that could not be sought after by the other teams. In this regard, the five players on each team that were reserved had no right to switch teams if they found the conditions deplorable or found that they could make more money elsewhere. Eventually this clause would be written into all contracts, and players who chose to dishonor the clause were blacklisted from organized baseball. Opposition to the reserve clause became a rallying point for the players, and several unions were formed over the next few decades in an attempt to give players bargaining leverage and a bigger voice. The Brotherhood of Professional Base Ball Players (1885), the Players Protective Association (1900), the Baseball Players’ Fraternity (1912), the National Baseball Players’ Association of the United States (1922), and the Association of Professional Ballplayers (1924) all had formed, in part, to oppose the reserve clause. However, those unions had trouble sustaining member interest and financial backing and eventually disbanded. During the time of these unions’ formations, the anti-union sentiment was high among the general public due to several highly publicized instances of labor union violence. The unions’ failures meant the owners maintained complete control over their players’ salaries, benefits, and livelihoods. Illegal Restraint of Trade? By restricting the movement of labor from team to team, which in almost all cases would be over state lines, it seemed to many that the owners were illegally restraining trade, a violation of the Sherman Antitrust Act. Several legal challenges were mounted against organized baseball by rival start-up leagues who were angered when they were denied access to the player market. In 1922, the United States Supreme Court ruled that baseball was a sport, not a business, and since it was conducted in local ballparks for local fans, it was mainly involved in intrastate commerce. The Federal Baseball Club v. National League decision (aka the Holmes decision, named after Judge Oliver Wendell Holmes) would ultimately give baseball an “antitrust exemption.” In 1953, the Supreme Court would reaffirm the ruling after a player (George Toolson of the New York Yankees) filed suit, claiming the reserve clause was illegal and was threatening his livelihood. Chief Justice Earl Warren reiterated that baseball “was not within the scope of federal antitrust laws,”1 and that action taken against the exemption should be by the U.S. Congress, not the courts. The reserve clause would remain untouched and embedded in players’ contracts until the mid-1970s. The Major League Baseball Players Association In 1946, a Mexican league was hiring several prominent U.S. players, creating competitive pressure on American player salaries. U.S. owners wanted to avoid a bidding war with the Mexican League. That same year, a labor lawyer convinced U.S. players to organize the American Baseball Guild. This union’s existence concerned management enough to cause them to bargain over a uniform players’ contract. The contract called for a minimum player salary ($5,000) and a guaranteed pension plan. Players contributed the bulk of the retirement funds, paying into the pension plan until their tenth season; owners contributed to it primarily from radio, television, and post-season ticket revenue. The union was short-lived, fading into obscurity by the end of that same year; however, the pension fund endured. By the early 1950s funds for the pension plan fell short, and the players felt it was in their best interest to organize once again. In 1953, the Major League Baseball Players Association (MLBPA) was formed to serve as the players’ main bargaining body and the owners implicitly voluntarily recognized the union by allowing it to operate the pension fund and by contributing to the fund. The union was led by player representatives and legal advisors until 1965 when it hired its first full-time executive, Marvin Miller, an economist with the Steelworkers Union. Miller brought with him experience in industrial relations and a hard-line bargaining approach. In response, the owners formed the Major League Player Relations Committee (PRC) to serve as their negotiating body. In 1968, the two sides hammered out the 1st Basic Agreement, a uniform contract that established (among other things) a formal grievance procedure for players and a significantly increased minimum salary level. Baseball historian Lee Lowenfish writes, “[the owners] conceded more rights in the 1st Basic Agreement than in all previous decades of the sport.”2 The Early 1970s: Players Challenge the Reserve Clause In 1972, the MLBPA and the PRC ran into trouble while negotiating the 3rd Basic Agreement. The major disagreement between the two sides stemmed from the amount the owners were willing to contribute to the players’ pension fund. Players union head Marvin Miller claimed that there was a surplus of pension funding that could be used to offset increased cost-of-living expenses that the players had been incurring. The owners showed solidarity (which has been rare throughout the league’s history) by refusing the MLBPA’s demands. The union even went so far as to file an “unfair labor practice” claim with the National Labor Relations Board when the owners refused to share certain financial information with them (the information was eventually provided). On April 1, 1972, a day that the Sporting News would call “the darkest day in sports history,”3 the players went on strike. The strike did not last long, as the two sides eventually reached a compromise on the contribution amount ($500,000). The half-million dollars that the players received in increased pension contributions was far less than the salary losses they incurred during the two-week long strike. The owners, who had talked the union down from their initial proposal of a $1 million increase in contributions, had lost $5.2 million in revenue.4 Shortly after the strike of 1972, the reserve clause was threatened once again. Outfielder Curt Flood of the St. Louis Cardinals challenged the legality of the reserve clause in court, and in Flood v. Kuhn, the Supreme Court once again upheld the Holmes decision. Flood was successful, however, in attracting Congress’s and the media’s attention to the reserve clause issue. In 1974, pitcher Catfish Hunter sought to become the league’s first free agent when the owner of his team (the Oakland A’s) dishonored a provision in his contract. Hunter’s case went to a three-man arbitration panel, which had been created and outlined in the 3rd Basic Agreement. The panel voted 2 to 1 that Hunter had the right to “shop his services” to other clubs since his own club did not honor the legally binding contract. Hunter became baseball’s first free agent. A year later, two players (Dave McNally and Andy Messersmith) challenged the clause once again. The two teams that held the rights to McNally and Messersmith had renewed the players’ contracts for the 1975 season, and for different reasons, both players refused to sign them. They played out the season anyway, without being under contract, and when the season concluded, the clubs employed the reserve clause once again. The players claimed that the reserve clause only provided that clubs could renew the contracts for one year, and that since they were not under contract during the 1975 season, the clubs were not within their rights to renew them for the 1976 season. The case went to arbitration, and by a 2 to 1 vote, the McNally and Messersmith won. The players had won the right to offer their services to the highest bidder (a process called “free agency”), and the reserve clause was dead. The new labor environment would become even more turbulent as free agency shook the economics of the game to its core. 1976 to 1989: Free Agency Becomes the Norm In 1976, the MLBPA and the PRC were split on the new free agency issue. The owners wanted players to gain free agency eligibility after 10 years of professional service, while the union proposed a five-year requirement. During Spring Training, the owners instituted a lockout. Commissioner Bowie Kuhn, who was technically an “employee of the owners,” ordered the owners to end the lockout, a move that lost him favor with many on the management side. The two sides eventually agreed on an eligibility minimum of six years of professional service, and compensation in the form of a draft pick for the team who was losing the player. Prior to the start of the 1980 season, the two sides were again far apart when negotiating the 5th Basic Agreement. The major issue was the compensation that a team would receive after losing a free agent. The proposals that the PRC presented were seen by Marvin Miller as an attempt to “dismantle free agency in its infancy.”5 On April 1, the players again went on strike. They agreed to start the season on the scheduled opening day, but promised to resume the strike on May 23 (the week that attendance usually plateaued) if no agreement had been reached. On the morning of May 23, the two sides reached a deal which basically provided that the free-agent compensation issue be studied for a year, after which negotiations regarding the issue would reopen. The committee that was selected to study the issue produced nothing substantial, and in 1981, the two sides were again having trouble finding common ground. The MLBPA’s Marvin Miller and the PRC’s president Ray Grebey had developed a bitter rivalry that the press could not get enough of. On May 29, the players went on strike once again. The strike lasted 50 days. The National Labor Relations Board, Congress’s Federal Mediation and Conciliation Services, and the Department of Labor all attempted to help the parties end their strike. On July 31, the two sides reached a deal that would provide the team losing a free agent compensation. The team that lost the player would receive a player from the “signing” team. The union won a free agency system that was similar to their own bargaining position—but at a heavy price. Players lost a total of $30 million in wages, and the owners lost roughly $72 million in revenues.6 Miller, Grebey, Kuhn, and other key figures in the negotiation process left their positions, and baseball witnessed labor peace and an attendance boom over the next four years. In 1985, with Donald Fehr heading the MLBPA, the two sides were determined to avoid a work stoppage while negotiating the 6th Basic Agreement. The two main issues that divided the two sides were once again free agent compensation and pension contribution levels. Several issues were agreed upon early (e.g., a drug review board would investigate cases where a player was accused of using cocaine), but it was still not enough to avoid another work stoppage. On August 6, the players went on strike, but with the 1981 strike still fresh in their minds, the two sides reached an agreement within a day. The risk of alienating the fans, who were spending more money than ever on baseball, proved to be the driving force behind the speedy resolution. The Early 1990s: Salary Arbitration, Revenue Sharing, and “The Big Strike” In 1990, the owners instituted another lockout while bargaining with the union over the 7th Basic Agreement. The disparity between large market teams (such as the New York Yankees and Los Angeles Dodgers) and small market teams (such as the Kansas City Royals and Milwaukee Brewers) was growing. With a larger fan base, large market teams were able to attract significantly richer television contracts from local networks. Because no salary cap existed, large market teams could sign better players due to their ability to offer high salaries. The owners saw this as a major problem, and proposed a “revenue sharing” program, in which large market teams would share a certain portion of their local revenue with small market teams. Their justification was that by increasing competitive balance, playoff races would be closer, attracting more people to the ballparks late in the season and producing higher television ratings. The union opposed a revenue sharing proposal because, if the large market teams had less money, they could not afford to offer top dollar contracts to free agents. Players employed by teams that received revenue sharing would not necessarily benefit either, because those teams were not obligated to spend the funds on player salaries. The owners tried to preempt a strike by locking the players out of spring training. After 32 days, an agreement was reached; the revenue sharing issue was put on hold. In 1994, the owners realized that not only was competitive and financial disparity hurting their profits, but salary arbitration was driving up salary levels. Beginning with the 1985 contract, players with three years of major-league service who felt that they were underpaid could demand that their salaries be adjusted upward through a process called “final offer arbitration.” The process worked as follows: The player’s representative presented evidence that the player was underpaid, relative to peers with comparable records. The team owner’s representative presented evidence that the player was equitably compensated, given other players in his peer group. Each side proposed a salary figure. The arbitrator then had to select either the player’s proposal or the owner’s proposal. Teams had been more inclined to pay players a little bit more than what they were worth instead of risking a loss in the final-offer arbitration process (where they stood to pay considerably more). The owners suggested an overhaul of the entire economic structure of the league: eliminating salary arbitration, phasing in a “salary cap” (where a team’s total payroll was limited to a specified amount), lowering free agency eligibility, and splitting television revenue 50/50 with the players. Fehr and the MLBPA, on the other hand, rejected these proposals. On August 11, 1994, the players went on strike. This time, the strike lasted 232 days, and the World Series was cancelled for the first time ever. The courts, the NLRB, Congress, the FMCS, and President Clinton all intervened at some point during the stoppage. The strike eventually ended when Judge Sonia Sotomayor of the United States District Court in Manhattan granted the NLRB’s request for an injunction. The NLRB was claiming that the owners had implemented their proposals during the strike without the existence of a good-faith impasse. Baseball resumed on April 26, 1995, with the old contract provisions being re-implemented. Historian Paul Staudohar calls the strike “one of the most eventful, but unproductive, ever.”7 The owners estimated their total losses to be in upwards of $1 billion, and the players saw their salaries drop considerably as cash-strapped clubs sought cheaper talent from the minor leagues. Some fans turned to minor league teams for baseball entertainment; others abandoned the game altogether. Meanwhile bargaining continued. The 8th Basic Agreement wasn’t agreed upon until late December, 1996. A revenue sharing program was implemented, but the owners did not receive their highly sought salary cap. Labor Relations Developments from 1998 to 2002: The Curt Flood Act and Contraction In 1998, Congress passed the Curt Flood Act. The law called for an end to baseball’s storied antitrust exemption, but only as it applied to labor relations. The premise of the bill was to “reduce the chance of future strikes by allowing players to bring an antitrust suit against the owners if labor negotiations stall.”8 All other aspects of the exemption still applied. In July 2000, the owners tried to partially rectify the problem of competitive and financial disparity by eliminating (or contracting) two teams from Major League Baseball. Their rationalization was that by having two of the poorly performing clubs gone, the revenue sharing burden would be eased substantially. Congress unsuccessfully attempted to stop the contraction, and the union responded by filing a grievance. Eventually, the owner of the Montreal Expos (one of the teams that was being considered for contraction) sold his team to an ownership group made up of the other 29 owners for $120 million. They moved the team to Washington, D.C., renamed it the Nationals, and then found a buyer for the team.9 The issue of contraction was put on hold. In 2002, the two sides entered a bargaining process that was calmer and more productive than in previous bargaining sessions. The owners wanted to implement a “luxury tax” (a team exceeding a certain payroll threshold would pay money to MLB and those funds would be redistributed among the other teams) and a competitive balance draft (the eight worst teams could select players from the eight best teams). Fehr and the union opposed these provisions (the original proposal by the owners was a 50 percent tax on all salary spending over $84 million), and disagreements over a proposed expansion of the drug testing policy also arose. The union set a strike date of August 30, and the two sides struck a deal the night before the work stoppage was to take place. A luxury tax with higher thresholds than originally proposed was implemented as a way to slow rising player salaries, and, perhaps just as importantly, the post-season (which accounts for a large portion of baseball’s revenue) was saved. The Upcoming 10th Basic Agreement The 2002 contract was set to expire in December 2006. The history of labor relations in professional baseball—the lost revenue from strikes and lockouts, attempts to control escalating players’ salaries, and clauses found in prior contracts—all cast a long shadow over the 2006 negotiations. Baseball Commissioner Allen H. (Bud) Selig issued an order to all MLB employees that no one outside of his office was to discuss upcoming labor negotiations. While the MLBPA’s Fehr planned to travel to each of the teams to listen to player concerns in the early spring, as of December 2005 the following issues seemed prominent: 1. Steroids In the fall of 2005, with negotiations over the 10th Basic Agreement still months away, the two sides were forced to bargain over a drug testing program. The endless media coverage over certain players’ alleged steroid usage was harming Major League Baseball’s image greatly, and Congress (most notably Senator John McCain, R-Arizona) had been threatening to act if the two sides could not develop a tougher policy.10 The controversy began when a book by ex-slugger Jose Canseco claimed to reveal the extent to which major league ballplayers were using and abusing steroids. The steroid issue had been gaining momentum for several years prior, as home-run records were broken and balls were flying out of the park like never before. In what some say was an attempt to garner media attention and solidify anti-drug stances with the public, several Congressmen became involved, even subpoenaing several former players and executives to testify in front of the Government Reform Committee in March of 2005.11 The MLBPA complained that the union should be contacted before either current or former players spoke out publicly on this issue. Fehr and Commissioner Selig were far apart on the issue of punishment for steroid users, with Fehr’s proposal being far more lenient than Selig’s.12 Fehr was calling for suspensions of 20 games for the first time a player was tested positive for steroids, 75 games for the second penalty (with some flexibility, based on circumstances), and a lifetime ban for the third penalty. Selig countered with an absolute ban of 50 games for the first penalty, 100 games for the second penalty, and a lifetime ban “for anybody dumb enough to be caught a third time.”13 Congress was threatening to act if the two sides could not voluntarily agree on a drug testing program for steroids. Amphetamines also became a topic for discussion. Owners wanted to expand the drug testing program to include amphetamines, albeit with lighter penalties than for steroids. The union leadership generally opposed this expansion of the drug testing program, but again Fehr was sensitive to Congressional pressure. 2. Contraction In 2002, “contraction”—a possible decrease in the number of MLB teams and/or relocation of poorly performing clubs—was a prominent topic. However, with the transformation of the Montreal Expos into the Washington, D.C. Nationals, it was unlikely that the topic would be a part of the 2006 negotiations; the owners had sent signals that contraction was no longer a pressing issue. However, it was possible that the topic could reemerge, if only as a “throw-away” issue. The 9th Basic Agreement stated that the owners had until July 2006 to notify the union of contraction/relocation plans. 3. The “Luxury Tax” Financial disparity was a topic that the PRC would certainly not consider to be “throw-away” issues. Owners argued that because some teams could afford to pay high salaries, they could hire the best players and make it unlikely that most other teams could make the playoffs. To restore competitive parity, the owners wanted to continue, and even expand, the luxury tax that had been implemented in 2002. The players union remained philosophically opposed to any formula such as the luxury tax (which they considered to be a type of flexible salary cap) that might hurt player incomes. However, as Murray Chass of The New York Times wrote, “. . . the owners would be hard pressed to make proposals based on economic hardship. Industry revenues didn’t reach $2 billion until 1997, and last year [2005] it soared to $4.7 billion.”14 The luxury tax which was laid out in the 9th Basic Agreement only affected a few teams (most of the penalties were paid by the New York Yankees), so both sides could have trouble proving or disproving its worth. It started in 2003 with a tax threshold of $117 million and rose to $136.5 million in 2006. Certain alterations to the complicated tax formula—the tax increased with each offense—could be proposed during bargaining, but it was doubtful that team owners would agree to a complete overhaul of the system so early in its existence. 4. Revenue Sharing In addition to the luxury tax, MLB used revenue sharing (e.g., from television contract rights and ticket sales) to distribute income from the most profitable teams to the least profitable teams. In 2004 and 2005, Major League Baseball witnessed its highest attendance levels ever, with 73,022,969 and 74,915,268 fans passing through the turnstiles, respectively.15 With luxury box and ticket prices rising, this attendance boom signaled an unprecedented rise in gate revenue. While this helped improve the profitability of the smaller-market teams, the union was concerned about how these funds were used. Minimum team salary levels needed to be addressed. After the Florida Marlins club received luxury tax and revenue sharing funds, it slashed its payroll to $15 million ($20 million less than the second lowest payroll). To the union leaders, such a move exposed holes in the revenue sharing program—in effect, funds were being transferred from some owners to other owners, but there was no guarantee that the players would see any of those funds. 5. Salary Levels The average salary earned by a MLB player rose 7 percent—about double the inflation rate for 2005. The average MLB player certainly seemed well-paid, with a 2005 salary of $2.4 million. However, this figure was skewed by the very high salaries paid to star players, some of whom earned over $20 million annually. The minimum annual salary was $327,000. The union wanted to increase that minimum. 6. Salary Arbitration and Free Agency How long one must play before becoming eligible for salary arbitration and/or free agency remained an issue. The union wanted to shorten the length of time so that high-performing players could increase their income to be comparable to their peers. The owners wanted to keep it where it was, or perhaps even lengthen the eligibility requirements. The appropriate compensation a signing team should pay to the team losing a free agent also remained a topic of potential discussion in contract negotiations. 7. Pension Contribution Levels The union wanted owners to increase their contributions to the player’s pension fund. Owners balked at this request, citing declining television revenues, which were used to fund pension contributions. The World Series television contract that Major League Baseball could sign with the FOX network might be the X-factor in the owners’ approach to bargaining over economic matters. A large percentage of baseball’s revenues came from national broadcasting contracts, which gave a network the right to broadcast playoff games, the All-Star Game, and a certain number of games throughout the regular season. The previous contract with FOX, which ran from 2000 through 2006, was worth $2.5 billion, but unfortunately coincided with the lowest television ratings in the sport’s history. The World Series ratings in 2000, 2002, and 2005 were the three lowest-rated broadcasts since the Series began airing in 1968.16 Because of this surprising trend, the new contract with FOX, which was to be signed in July of 2006, was rumored to be worth significantly less (estimated at $1.75 billion over seven years).17 Since the owners used large portions of the television contract to fund the players’ pension fund, the claim of financial hardship by the PRC could rear its ugly head during Basic Agreement negotiations. 8. Strike Risks The potential alienation of baseball’s fan base by undergoing another work stoppage might prove to exert more influence over bargaining matters than any other factor. Past work stoppages had cost both players and owners significant amounts of money. A strike could result in team owners attempting to bring in “scab” players (e.g., minor league players) or it could result in the decertification of the union by disgruntled players. 9. The Media and Public Perception Finally, with any labor relations situation, the media play an important role in the approaches that the two sides take to bargaining. In prior negotiations, national media attention to labor contract negotiations was considerably more intense than in other industries. The ESPN television network only added to the scrutiny as it complemented traditional media outlets, such as Sports Illustrated magazine and the USA Today, New York Times, and Washington Post newspapers. The MLBPA was recently accused of shielding drug addicts and criminals because of its stance on steroid testing. Yet to give in to owner demands for a tough new drug testing policy would only lead to media criticism that “the strongest union in America” was ineffective and could be beaten by determined owners. Such criticism could cause some union leaders to encourage taking a hard-line approach to regain the confidence of their constituents. The Big Decision: What Bargaining Strategy Should Fehr Adopt? Donald Fehr realized that he could go one of two ways when the bargaining sessions were to begin during the 2006 season. On one hand, he could probably secure the “basic” increases in minimum salary and pension contributions without a lot of resistance from the PRC and its leader, Commissioner Bug Selig. Although the owners might claim that the decreased television revenue put them in a less desirable financial position, Fehr knew that he could retaliate by going to the media with the astronomical industry revenue figures that baseball was currently realizing. With gate revenues and industry profits at an all time high, a hard-line approach and the threat of a strike or anti-trust lawsuit might allow the union to secure better wages and benefits than they had ever imagined. On the other hand, Fehr knew that the public image of the union had suffered because of past “strikes by millionaires” and because of the union’s current resistance to a tougher steroid policy. As Fehr mulled his options and planned his bargaining strategy, he perhaps hoped that Jose Canseco wasn’t planning on writing another book anytime soon. Source: This case was prepared by Daniel T. Romportl and William H. Ross, Jr., both of the University of Wisconsin–La Crosse. Used with permission from the authors and the Society for Case Research.

Cultural Influences On Perception

Respond to the following prompt in a primary post of at least 150 words.

Sensation refers to an actual event; perception refers to how we interpret the event. What are some cultural differences that might affect responses to particular stimuli? In other words: provide an example of something that people from two different cultures may perceive in completely different ways (for example holding up two fingers, with palm facing the signer, is a very rude hand gesture for folks in the U.K., but in America, we hold up two fingers to mean “peace”). Create a post using examples from the text as well as your own experiences. This post should be completed by 11:59pm PST on Thursday to give your peers lots of time to create meaningful responses.

  • Chapter 5

    Sensation and Perception

    Figure 5.1 If you were standing in the midst of this street scene, you would be absorbing and processing numerous pieces of sensory input. (credit: modification of work by Cory Zanker)

    Chapter Outline 5.1 Sensation versus Perception 5.2 Waves and Wavelengths 5.3 Vision 5.4 Hearing 5.5 The Other Senses 5.6 Gestalt Principles of Perception

    Introduction Imagine standing on a city street corner. You might be struck by movement everywhere as cars and people go about their business, by the sound of a street musician’s melody or a horn honking in the distance, by the smell of exhaust fumes or of food being sold by a nearby vendor, and by the sensation of hard pavement under your feet.

    We rely on our sensory systems to provide important information about our surroundings. We use this information to successfully navigate and interact with our environment so that we can find nourishment, seek shelter, maintain social relationships, and avoid potentially dangerous situations.

    This chapter will provide an overview of how sensory information is received and processed by the nervous system and how that affects our conscious experience of the world. We begin by learning the distinction between sensation and perception. Then we consider the physical properties of light and sound stimuli, along with an overview of the basic structure and function of the major sensory systems. The chapter will close with a discussion of a historically important theory of perception called Gestalt.

    Chapter 5 | Sensation and Perception 149

     

     

    5.1 Sensation versus Perception

    Learning Objectives

    By the end of this section, you will be able to: • Distinguish between sensation and perception • Describe the concepts of absolute threshold and difference threshold • Discuss the roles attention, motivation, and sensory adaptation play in perception

    SENSATION What does it mean to sense something? Sensory receptors are specialized neurons that respond to specific types of stimuli. When sensory information is detected by a sensory receptor, sensation has occurred. For example, light that enters the eye causes chemical changes in cells that line the back of the eye. These cells relay messages, in the form of action potentials (as you learned when studying biopsychology), to the central nervous system. The conversion from sensory stimulus energy to action potential is known as transduction.

    You have probably known since elementary school that we have five senses: vision, hearing (audition), smell (olfaction), taste (gustation), and touch (somatosensation). It turns out that this notion of five senses is oversimplified. We also have sensory systems that provide information about balance (the vestibular sense), body position and movement (proprioception and kinesthesia), pain (nociception), and temperature (thermoception).

    The sensitivity of a given sensory system to the relevant stimuli can be expressed as an absolute threshold. Absolute threshold refers to the minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time. Another way to think about this is by asking how dim can a light be or how soft can a sound be and still be detected half of the time. The sensitivity of our sensory receptors can be quite amazing. It has been estimated that on a clear night, the most sensitive sensory cells in the back of the eye can detect a candle flame 30 miles away (Okawa & Sampath, 2007). Under quiet conditions, the hair cells (the receptor cells of the inner ear) can detect the tick of a clock 20 feet away (Galanter, 1962).

    It is also possible for us to get messages that are presented below the threshold for conscious awareness—these are called subliminal messages. A stimulus reaches a physiological threshold when it is strong enough to excite sensory receptors and send nerve impulses to the brain: This is an absolute threshold. A message below that threshold is said to be subliminal: We receive it, but we are not consciously aware of it. Over the years there has been a great deal of speculation about the use of subliminal messages in advertising, rock music, and self-help audio programs. Research evidence shows that in laboratory settings, people can process and respond to information outside of awareness. But this does not mean that we obey these messages like zombies; in fact, hidden messages have little effect on behavior outside the laboratory (Kunst-Wilson & Zajonc, 1980; Rensink, 2004; Nelson, 2008; Radel, Sarrazin, Legrain, & Gobancé, 2009; Loersch, Durso, & Petty, 2013).

    Absolute thresholds are generally measured under incredibly controlled conditions in situations that are optimal for sensitivity. Sometimes, we are more interested in how much difference in stimuli is required to detect a difference between them. This is known as the just noticeable difference (jnd) or difference threshold. Unlike the absolute threshold, the difference threshold changes depending on the stimulus intensity. As an example, imagine yourself in a very dark movie theater. If an audience member were to receive a text message on her cell phone which caused her screen to light up, chances are that many people would notice the change in illumination in the theater. However, if the same thing happened in a brightly lit arena during a basketball game, very few people would notice. The cell phone brightness does not change, but its ability to be detected as a change in illumination varies dramatically between the two contexts. Ernst Weber proposed this theory of change in difference threshold in the 1830s, and it has become known as Weber’s law: The difference threshold is a constant fraction of the original stimulus, as

    150 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    the example illustrates.

    PERCEPTION While our sensory receptors are constantly collecting information from the environment, it is ultimately how we interpret that information that affects how we interact with the world. Perception refers to the way sensory information is organized, interpreted, and consciously experienced. Perception involves both bottom-up and top-down processing. Bottom-up processing refers to the fact that perceptions are built from sensory input. On the other hand, how we interpret those sensations is influenced by our available knowledge, our experiences, and our thoughts. This is called top-down processing.

    One way to think of this concept is that sensation is a physical process, whereas perception is psychological. For example, upon walking into a kitchen and smelling the scent of baking cinnamon rolls, the sensation is the scent receptors detecting the odor of cinnamon, but the perception may be “Mmm, this smells like the bread Grandma used to bake when the family gathered for holidays.”

    Although our perceptions are built from sensations, not all sensations result in perception. In fact, we often don’t perceive stimuli that remain relatively constant over prolonged periods of time. This is known as sensory adaptation. Imagine entering a classroom with an old analog clock. Upon first entering the room, you can hear the ticking of the clock; as you begin to engage in conversation with classmates or listen to your professor greet the class, you are no longer aware of the ticking. The clock is still ticking, and that information is still affecting sensory receptors of the auditory system. The fact that you no longer perceive the sound demonstrates sensory adaptation and shows that while closely associated, sensation and perception are different.

    There is another factor that affects sensation and perception: attention. Attention plays a significant role in determining what is sensed versus what is perceived. Imagine you are at a party full of music, chatter, and laughter. You get involved in an interesting conversation with a friend, and you tune out all the background noise. If someone interrupted you to ask what song had just finished playing, you would probably be unable to answer that question.

    See for yourself how inattentional blindness works by checking out this selective attention test (http://openstaxcollege.org/l/blindness) from Simons and Chabris (1999).

    One of the most interesting demonstrations of how important attention is in determining our perception of the environment occurred in a famous study conducted by Daniel Simons and Christopher Chabris (1999). In this study, participants watched a video of people dressed in black and white passing basketballs. Participants were asked to count the number of times the team in white passed the ball. During the video, a person dressed in a black gorilla costume walks among the two teams. You would think that someone would notice the gorilla, right? Nearly half of the people who watched the video didn’t notice the gorilla at all, despite the fact that he was clearly visible for nine seconds. Because participants were so focused on the number of times the white team was passing the ball, they completely tuned out other visual information. Failure to notice something that is completely visible because of a lack of attention is called inattentional blindness.

    In a similar experiment, researchers tested inattentional blindness by asking participants to observe images moving across a computer screen. They were instructed to focus on either white or black objects, disregarding the other color. When a red cross passed across the screen, about one third of subjects did not

    LINK TO LEARNING

    Chapter 5 | Sensation and Perception 151

     

     

    notice it (Figure 5.2) (Most, Simons, Scholl, & Chabris, 2000).

    Figure 5.2 Nearly one third of participants in a study did not notice that a red cross passed on the screen because their attention was focused on the black or white figures. (credit: Cory Zanker)

    Motivation can also affect perception. Have you ever been expecting a really important phone call and, while taking a shower, you think you hear the phone ringing, only to discover that it is not? If so, then you have experienced how motivation to detect a meaningful stimulus can shift our ability to discriminate between a true sensory stimulus and background noise. The ability to identify a stimulus when it is embedded in a distracting background is called signal detection theory. This might also explain why a mother is awakened by a quiet murmur from her baby but not by other sounds that occur while she is asleep. Signal detection theory has practical applications, such as increasing air traffic controller accuracy. Controllers need to be able to detect planes among many signals (blips) that appear on the radar screen and follow those planes as they move through the sky. In fact, the original work of the researcher who developed signal detection theory was focused on improving the sensitivity of air traffic controllers to plane blips (Swets, 1964).

    Our perceptions can also be affected by our beliefs, values, prejudices, expectations, and life experiences. As you will see later in this chapter, individuals who are deprived of the experience of binocular vision during critical periods of development have trouble perceiving depth (Fawcett, Wang, & Birch, 2005). The shared experiences of people within a given cultural context can have pronounced effects on perception. For example, Marshall Segall, Donald Campbell, and Melville Herskovits (1963) published the results of a multinational study in which they demonstrated that individuals from Western cultures were more prone to experience certain types of visual illusions than individuals from non-Western cultures, and vice versa. One such illusion that Westerners were more likely to experience was the Müller-Lyer illusion (Figure 5.3): The lines appear to be different lengths, but they are actually the same length.

    152 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    Figure 5.3 In the Müller-Lyer illusion, lines appear to be different lengths although they are identical. (a) Arrows at the ends of lines may make the line on the right appear longer, although the lines are the same length. (b) When applied to a three-dimensional image, the line on the right again may appear longer although both black lines are the same length.

    These perceptual differences were consistent with differences in the types of environmental features experienced on a regular basis by people in a given cultural context. People in Western cultures, for example, have a perceptual context of buildings with straight lines, what Segall’s study called a carpentered world (Segall et al., 1966). In contrast, people from certain non-Western cultures with an uncarpentered view, such as the Zulu of South Africa, whose villages are made up of round huts arranged in circles, are less susceptible to this illusion (Segall et al., 1999). It is not just vision that is affected by cultural factors. Indeed, research has demonstrated that the ability to identify an odor, and rate its pleasantness and its intensity, varies cross-culturally (Ayabe-Kanamura, Saito, Distel, Martínez-Gómez, & Hudson, 1998).

    Children described as thrill seekers are more likely to show taste preferences for intense sour flavors (Liem, Westerbeek, Wolterink, Kok, & de Graaf, 2004), which suggests that basic aspects of personality might affect perception. Furthermore, individuals who hold positive attitudes toward reduced-fat foods are more likely to rate foods labeled as reduced fat as tasting better than people who have less positive attitudes about these products (Aaron, Mela, & Evans, 1994).

    5.2 Waves and Wavelengths

    Learning Objectives

    By the end of this section, you will be able to: • Describe important physical features of wave forms • Show how physical properties of light waves are associated with perceptual experience • Show how physical properties of sound waves are associated with perceptual experience

    Visual and auditory stimuli both occur in the form of waves. Although the two stimuli are very different in terms of composition, wave forms share similar characteristics that are especially important to our visual and auditory perceptions. In this section, we describe the physical properties of the waves as well as the perceptual experiences associated with them.

    AMPLITUDE AND WAVELENGTH Two physical characteristics of a wave are amplitude and wavelength (Figure 5.4). The amplitude of a

    Chapter 5 | Sensation and Perception 153

     

     

    wave is the height of a wave as measured from the highest point on the wave (peak or crest) to the lowest point on the wave (trough). Wavelength refers to the length of a wave from one peak to the next.

    Figure 5.4 The amplitude or height of a wave is measured from the peak to the trough. The wavelength is measured from peak to peak.

    Wavelength is directly related to the frequency of a given wave form. Frequency refers to the number of waves that pass a given point in a given time period and is often expressed in terms of hertz (Hz), or cycles per second. Longer wavelengths will have lower frequencies, and shorter wavelengths will have higher frequencies (Figure 5.5).

    Figure 5.5 This figure illustrates waves of differing wavelengths/frequencies. At the top of the figure, the red wave has a long wavelength/short frequency. Moving from top to bottom, the wavelengths decrease and frequencies increase.

    LIGHT WAVES The visible spectrum is the portion of the larger electromagnetic spectrum that we can see. As Figure 5.6 shows, the electromagnetic spectrum encompasses all of the electromagnetic radiation that occurs in our environment and includes gamma rays, x-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves. The visible spectrum in humans is associated with wavelengths that range from 380 to 740 nm—a very small distance, since a nanometer (nm) is one billionth of a meter. Other species can detect other portions of the electromagnetic spectrum. For instance, honeybees can see light in the ultraviolet range (Wakakuwa, Stavenga, & Arikawa, 2007), and some snakes can detect infrared radiation in addition to more traditional visual light cues (Chen, Deng, Brauth, Ding, & Tang, 2012; Hartline, Kass, & Loop, 1978).

    154 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    Figure 5.6 Light that is visible to humans makes up only a small portion of the electromagnetic spectrum.

    In humans, light wavelength is associated with perception of color (Figure 5.7). Within the visible spectrum, our experience of red is associated with longer wavelengths, greens are intermediate, and blues and violets are shorter in wavelength. (An easy way to remember this is the mnemonic ROYGBIV: red, orange, yellow, green, blue, indigo, violet.) The amplitude of light waves is associated with our experience of brightness or intensity of color, with larger amplitudes appearing brighter.

    Figure 5.7 Different wavelengths of light are associated with our perception of different colors. (credit: modification of work by Johannes Ahlmann)

    SOUND WAVES Like light waves, the physical properties of sound waves are associated with various aspects of our perception of sound. The frequency of a sound wave is associated with our perception of that sound’s pitch. High-frequency sound waves are perceived as high-pitched sounds, while low-frequency sound waves are perceived as low-pitched sounds. The audible range of sound frequencies is between 20 and 20000 Hz, with greatest sensitivity to those frequencies that fall in the middle of this range.

    As was the case with the visible spectrum, other species show differences in their audible ranges. For instance, chickens have a very limited audible range, from 125 to 2000 Hz. Mice have an audible range from 1000 to 91000 Hz, and the beluga whale’s audible range is from 1000 to 123000 Hz. Our pet dogs and cats have audible ranges of about 70–45000 Hz and 45–64000 Hz, respectively (Strain, 2003).

    The loudness of a given sound is closely associated with the amplitude of the sound wave. Higher amplitudes are associated with louder sounds. Loudness is measured in terms of decibels (dB), a logarithmic unit of sound intensity. A typical conversation would correlate with 60 dB; a rock concert might check in at 120 dB (Figure 5.8). A whisper 5 feet away or rustling leaves are at the low end of our hearing range; sounds like a window air conditioner, a normal conversation, and even heavy traffic or a vacuum cleaner are within a tolerable range. However, there is the potential for hearing damage from

    Chapter 5 | Sensation and Perception 155

     

     

    about 80 dB to 130 dB: These are sounds of a food processor, power lawnmower, heavy truck (25 feet away), subway train (20 feet away), live rock music, and a jackhammer. The threshold for pain is about 130 dB, a jet plane taking off or a revolver firing at close range (Dunkle, 1982).

    Figure 5.8 This figure illustrates the loudness of common sounds. (credit “planes”: modification of work by Max Pfandl; credit “crowd”: modification of work by Christian Holmér; credit “blender”: modification of work by Jo Brodie; credit “car”: modification of work by NRMA New Cars/Flickr; credit “talking”: modification of work by Joi Ito; credit “leaves”: modification of work by Aurelijus Valeiša)

    Although wave amplitude is generally associated with loudness, there is some interaction between frequency and amplitude in our perception of loudness within the audible range. For example, a 10 Hz sound wave is inaudible no matter the amplitude of the wave. A 1000 Hz sound wave, on the other hand, would vary dramatically in terms of perceived loudness as the amplitude of the wave increased.

    Watch this brief video (http://openstaxcollege.org/l/frequency) demonstrating how frequency and amplitude interact in our perception of loudness.

    Of course, different musical instruments can play the same musical note at the same level of loudness, yet they still sound quite different. This is known as the timbre of a sound. Timbre refers to a sound’s purity, and it is affected by the complex interplay of frequency, amplitude, and timing of sound waves.

    LINK TO LEARNING

    156 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    5.3 Vision

    Learning Objectives

    By the end of this section, you will be able to: • Describe the basic anatomy of the visual system • Discuss how rods and cones contribute to different aspects of vision • Describe how monocular and binocular cues are used in the perception of depth

    The visual system constructs a mental representation of the world around us (Figure 5.9). This contributes to our ability to successfully navigate through physical space and interact with important individuals and objects in our environments. This section will provide an overview of the basic anatomy and function of the visual system. In addition, we will explore our ability to perceive color and depth.

    Figure 5.9 Our eyes take in sensory information that helps us understand the world around us. (credit “top left”: modification of work by “rajkumar1220″/Flickr”; credit “top right”: modification of work by Thomas Leuthard; credit “middle left”: modification of work by Demietrich Baker; credit “middle right”: modification of work by “kaybee07″/Flickr; credit “bottom left”: modification of work by “Isengardt”/Flickr; credit “bottom right”: modification of work by Willem Heerbaart)

    ANATOMY OF THE VISUAL SYSTEM The eye is the major sensory organ involved in vision (Figure 5.10). Light waves are transmitted across the cornea and enter the eye through the pupil. The cornea is the transparent covering over the eye. It serves as a barrier between the inner eye and the outside world, and it is involved in focusing light waves that enter the eye. The pupil is the small opening in the eye through which light passes, and the size of the pupil can change as a function of light levels as well as emotional arousal. When light levels are low, the pupil will become dilated, or expanded, to allow more light to enter the eye. When light levels are high, the pupil will constrict, or become smaller, to reduce the amount of light that enters the eye. The pupil’s size is controlled by muscles that are connected to the iris, which is the colored portion of the eye.

    Chapter 5 | Sensation and Perception 157

     

     

    Figure 5.10 The anatomy of the eye is illustrated in this diagram.

    After passing through the pupil, light crosses the lens, a curved, transparent structure that serves to provide additional focus. The lens is attached to muscles that can change its shape to aid in focusing light that is reflected from near or far objects. In a normal-sighted individual, the lens will focus images perfectly on a small indentation in the back of the eye known as the fovea, which is part of the retina, the light-sensitive lining of the eye. The fovea contains densely packed specialized photoreceptor cells (Figure 5.11). These photoreceptor cells, known as cones, are light-detecting cells. The cones are specialized types of photoreceptors that work best in bright light conditions. Cones are very sensitive to acute detail and provide tremendous spatial resolution. They also are directly involved in our ability to perceive color.

    While cones are concentrated in the fovea, where images tend to be focused, rods, another type of photoreceptor, are located throughout the remainder of the retina. Rods are specialized photoreceptors that work well in low light conditions, and while they lack the spatial resolution and color function of the cones, they are involved in our vision in dimly lit environments as well as in our perception of movement on the periphery of our visual field.

    158 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    Figure 5.11 The two types of photoreceptors are shown in this image. Rods are colored green and cones are blue.

    We have all experienced the different sensitivities of rods and cones when making the transition from a brightly lit environment to a dimly lit environment. Imagine going to see a blockbuster movie on a clear summer day. As you walk from the brightly lit lobby into the dark theater, you notice that you immediately have difficulty seeing much of anything. After a few minutes, you begin to adjust to the darkness and can see the interior of the theater. In the bright environment, your vision was dominated primarily by cone activity. As you move to the dark environment, rod activity dominates, but there is a delay in transitioning between the phases. If your rods do not transform light into nerve impulses as easily and efficiently as they should, you will have difficulty seeing in dim light, a condition known as night blindness.

    Rods and cones are connected (via several interneurons) to retinal ganglion cells. Axons from the retinal ganglion cells converge and exit through the back of the eye to form the optic nerve. The optic nerve carries visual information from the retina to the brain. There is a point in the visual field called the blind spot: Even when light from a small object is focused on the blind spot, we do not see it. We are not consciously aware of our blind spots for two reasons: First, each eye gets a slightly different view of the visual field; therefore, the blind spots do not overlap. Second, our visual system fills in the blind spot so that although we cannot respond to visual information that occurs in that portion of the visual field, we are also not aware that information is missing.

    The optic nerve from each eye merges just below the brain at a point called the optic chiasm. As Figure 5.12 shows, the optic chiasm is an X-shaped structure that sits just below the cerebral cortex at the front of the brain. At the point of the optic chiasm, information from the right visual field (which comes from both eyes) is sent to the left side of the brain, and information from the left visual field is sent to the right side of the brain.

    Chapter 5 | Sensation and Perception 159

     

     

    Figure 5.12 This illustration shows the optic chiasm at the front of the brain and the pathways to the occipital lobe at the back of the brain, where visual sensations are processed into meaningful perceptions.

    Once inside the brain, visual information is sent via a number of structures to the occipital lobe at the back of the brain for processing. Visual information might be processed in parallel pathways which can generally be described as the “what pathway” and the “where/how” pathway. The “what pathway” is involved in object recognition and identification, while the “where/how pathway” is involved with location in space and how one might interact with a particular visual stimulus (Milner & Goodale, 2008; Ungerleider & Haxby, 1994). For example, when you see a ball rolling down the street, the “what pathway” identifies what the object is, and the “where/how pathway” identifies its location or movement in space.

    COLOR AND DEPTH PERCEPTION We do not see the world in black and white; neither do we see it as two-dimensional (2-D) or flat (just height and width, no depth). Let’s look at how color vision works and how we perceive three dimensions (height, width, and depth).

    Color Vision Normal-sighted individuals have three different types of cones that mediate color vision. Each of these cone types is maximally sensitive to a slightly different wavelength of light. According to the trichromatic theory of color vision, shown in Figure 5.13, all colors in the spectrum can be produced by combining red, green, and blue. The three types of cones are each receptive to one of the colors.

    160 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    Figure 5.13 This figure illustrates the different sensitivities for the three cone types found in a normal-sighted individual. (credit: modification of work by Vanessa Ezekowitz)

    The trichromatic theory of color vision is not the only theory—another major theory of color vision is known as the opponent-process theory. According to this theory, color is coded in opponent pairs: black- white, yellow-blue, and green-red. The basic idea is that some cells of the visual system are excited by one of the opponent colors and inhibited by the other. So, a cell that was excited by wavelengths associated with green would be inhibited by wavelengths associated with red, and vice versa. One of the implications of opponent processing is that we do not experience greenish-reds or yellowish-blues as colors. Another implication is that this leads to the experience of negative afterimages. An afterimage describes the continuation of a visual sensation after removal of the stimulus. For example, when you stare briefly at the sun and then look away from it, you may still perceive a spot of light although the stimulus (the sun) has been removed. When color is involved in the stimulus, the color pairings identified in the opponent-process theory lead to a negative afterimage. You can test this concept using the flag in Figure 5.14.

    Chapter 5 | Sensation and Perception 161

     

     

    Figure 5.14 Stare at the white dot for 30–60 seconds and then move your eyes to a blank piece of white paper. What do you see? This is known as a negative afterimage, and it provides empirical support for the opponent-process theory of color vision.

    But these two theories—the trichromatic theory of color vision and the opponent-process theory—are not mutually exclusive. Research has shown that they just apply to different levels of the nervous system. For visual processing on the retina, trichromatic theory applies: the cones are responsive to three different wavelengths that represent red, blue, and green. But once the signal moves past the retina on its way to the brain, the cells respond in a way consistent with opponent-process theory (Land, 1959; Kaiser, 1997).

    Watch this video (http://openstaxcollege.org/l/colorvision) to see the first part of a documentary explaining color vision in more detail.

    Depth Perception Our ability to perceive spatial relationships in three-dimensional (3-D) space is known as depth perception. With depth perception, we can describe things as being in front, behind, above, below, or to the side of other things.

    Our world is three-dimensional, so it makes sense that our mental representation of the world has three- dimensional properties. We use a variety of cues in a visual scene to establish our sense of depth. Some of these are binocular cues, which means that they rely on the use of both eyes. One example of a binocular depth cue is binocular disparity, the slightly different view of the world that each of our eyes receives. To experience this slightly different view, do this simple exercise: extend your arm fully and extend one of your fingers and focus on that finger. Now, close your left eye without moving your head, then open your left eye and close your right eye without moving your head. You will notice that your finger seems to shift as you alternate between the two eyes because of the slightly different view each eye has of your finger.

    A 3-D movie works on the same principle: the special glasses you wear allow the two slightly different images projected onto the screen to be seen separately by your left and your right eye. As your brain processes these images, you have the illusion that the leaping animal or running person is coming right toward you.

    Although we rely on binocular cues to experience depth in our 3-D world, we can also perceive depth in

    LINK TO LEARNING

    162 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    2-D arrays. Think about all the paintings and photographs you have seen. Generally, you pick up on depth in these images even though the visual stimulus is 2-D. When we do this, we are relying on a number of monocular cues, or cues that require only one eye. If you think you can’t see depth with one eye, note that you don’t bump into things when using only one eye while walking—and, in fact, we have more monocular cues than binocular cues.

    An example of a monocular cue would be what is known as linear perspective. Linear perspective refers to the fact that we perceive depth when we see two parallel lines that seem to converge in an image (Figure 5.15). Some other monocular depth cues are interposition, the partial overlap of objects, and the relative size and closeness of images to the horizon.

    Figure 5.15 We perceive depth in a two-dimensional figure like this one through the use of monocular cues like linear perspective, like the parallel lines converging as the road narrows in the distance. (credit: Marc Dalmulder)

    Stereoblindness

    Bruce Bridgeman was born with an extreme case of lazy eye that resulted in him being stereoblind, or unable to respond to binocular cues of depth. He relied heavily on monocular depth cues, but he never had a true appreciation of the 3-D nature of the world around him. This all changed one night in 2012 while Bruce was seeing a movie with his wife.

    The movie the couple was going to see was shot in 3-D, and even though he thought it was a waste of money, Bruce paid for the 3-D glasses when he purchased his ticket. As soon as the film began, Bruce put on the glasses and experienced something completely new. For the first time in his life he appreciated the true depth of the world around him. Remarkably, his ability to perceive depth persisted outside of the movie theater.

    There are cells in the nervous system that respond to binocular depth cues. Normally, these cells require activation during early development in order to persist, so experts familiar with Bruce’s case (and others like his) assume that at some point in his development, Bruce must have experienced at least a fleeting moment of binocular vision. It was enough to ensure the survival of the cells in the visual system tuned to binocular cues. The mystery now is why it took Bruce nearly 70 years to have these cells activated (Peck, 2012).

    DIG DEEPER

    Chapter 5 | Sensation and Perception 163

     

     

    5.4 Hearing

    Learning Objectives

    By the end of this section, you will be able to: • Describe the basic anatomy and function of the auditory system • Explain how we encode and perceive pitch • Discuss how we localize sound

    Our auditory system converts pressure waves into meaningful sounds. This translates into our ability to hear the sounds of nature, to appreciate the beauty of music, and to communicate with one another through spoken language. This section will provide an overview of the basic anatomy and function of the auditory system. It will include a discussion of how the sensory stimulus is translated into neural impulses, where in the brain that information is processed, how we perceive pitch, and how we know where sound is coming from.

    ANATOMY OF THE AUDITORY SYSTEM The ear can be separated into multiple sections. The outer ear includes the pinna, which is the visible part of the ear that protrudes from our heads, the auditory canal, and the tympanic membrane, or eardrum. The middle ear contains three tiny bones known as the ossicles, which are named the malleus (or hammer), incus (or anvil), and the stapes (or stirrup). The inner ear contains the semi-circular canals, which are involved in balance and movement (the vestibular sense), and the cochlea. The cochlea is a fluid- filled, snail-shaped structure that contains the sensory receptor cells (hair cells) of the auditory system (Figure 5.16).

    Figure 5.16 The ear is divided into outer (pinna and tympanic membrane), middle (the three ossicles: malleus, incus, and stapes), and inner (cochlea and basilar membrane) divisions.

    Sound waves travel along the auditory canal and strike the tympanic membrane, causing it to vibrate. This vibration results in movement of the three ossicles. As the ossicles move, the stapes presses into a thin membrane of the cochlea known as the oval window. As the stapes presses into the oval window, the fluid inside the cochlea begins to move, which in turn stimulates hair cells, which are auditory receptor cells of the inner ear embedded in the basilar membrane. The basilar membrane is a thin strip of tissue within the cochlea.

    The activation of hair cells is a mechanical process: the stimulation of the hair cell ultimately leads to

    164 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    activation of the cell. As hair cells become activated, they generate neural impulses that travel along the auditory nerve to the brain. Auditory information is shuttled to the inferior colliculus, the medial geniculate nucleus of the thalamus, and finally to the auditory cortex in the temporal lobe of the brain for processing. Like the visual system, there is also evidence suggesting that information about auditory recognition and localization is processed in parallel streams (Rauschecker & Tian, 2000; Renier et al., 2009).

    PITCH PERCEPTION Different frequencies of sound waves are associated with differences in our perception of the pitch of those sounds. Low-frequency sounds are lower pitched, and high-frequency sounds are higher pitched. How does the auditory system differentiate among various pitches?

    Several theories have been proposed to account for pitch perception. We’ll discuss two of them here: temporal theory and place theory. The temporal theory of pitch perception asserts that frequency is coded by the activity level of a sensory neuron. This would mean that a given hair cell would fire action potentials related to the frequency of the sound wave. While this is a very intuitive explanation, we detect such a broad range of frequencies (20–20,000 Hz) that the frequency of action potentials fired by hair cells cannot account for the entire range. Because of properties related to sodium channels on the neuronal membrane that are involved in action potentials, there is a point at which a cell cannot fire any faster (Shamma, 2001).

    The place theory of pitch perception suggests that different portions of the basilar membrane are sensitive to sounds of different frequencies. More specifically, the base of the basilar membrane responds best to high frequencies and the tip of the basilar membrane responds best to low frequencies. Therefore, hair cells that are in the base portion would be labeled as high-pitch receptors, while those in the tip of basilar membrane would be labeled as low-pitch receptors (Shamma, 2001).

    In reality, both theories explain different aspects of pitch perception. At frequencies up to about 4000 Hz, it is clear that both the rate of action potentials and place contribute to our perception of pitch. However, much higher frequency sounds can only be encoded using place cues (Shamma, 2001).

    SOUND LOCALIZATION The ability to locate sound in our environments is an important part of hearing. Localizing sound could be considered similar to the way that we perceive depth in our visual fields. Like the monocular and binocular cues that provided information about depth, the auditory system uses both monaural (one-eared) and binaural (two-eared) cues to localize sound.

    Each pinna interacts with incoming sound waves differently, depending on the sound’s source relative to our bodies. This interaction provides a monaural cue that is helpful in locating sounds that occur above or below and in front or behind us. The sound waves received by your two ears from sounds that come from directly above, below, in front, or behind you would be identical; therefore, monaural cues are essential (Grothe, Pecka, & McAlpine, 2010).

    Binaural cues, on the other hand, provide information on the location of a sound along a horizontal axis by relying on differences in patterns of vibration of the eardrum between our two ears. If a sound comes from an off-center location, it creates two types of binaural cues: interaural level differences and interaural timing differences. Interaural level difference refers to the fact that a sound coming from the right side of your body is more intense at your right ear than at your left ear because of the attenuation of the sound wave as it passes through your head. Interaural timing difference refers to the small difference in the time at which a given sound wave arrives at each ear (Figure 5.17). Certain brain areas monitor these differences to construct where along a horizontal axis a sound originates (Grothe et al., 2010).

    Chapter 5 | Sensation and Perception 165

     

     

    Figure 5.17 Localizing sound involves the use of both monaural and binaural cues. (credit “plane”: modification of work by Max Pfandl)

    HEARING LOSS Deafness is the partial or complete inability to hear. Some people are born deaf, which is known as congenital deafness. Many others begin to suffer from conductive hearing loss because of age, genetic predisposition, or environmental effects, including exposure to extreme noise (noise-induced hearing loss, as shown in Figure 5.18), certain illnesses (such as measles or mumps), or damage due to toxins (such as those found in certain solvents and metals).

    Figure 5.18 Environmental factors that can lead to conductive hearing loss include regular exposure to loud music or construction equipment. (a) Rock musicians and (b) construction workers are at risk for this type of hearing loss. (credit a: modification of work by Kenny Sun; credit b: modification of work by Nick Allen)

    Given the mechanical nature by which the sound wave stimulus is transmitted from the eardrum through the ossicles to the oval window of the cochlea, some degree of hearing loss is inevitable. With conductive hearing loss, hearing problems are associated with a failure in the vibration of the eardrum and/or movement of the ossicles. These problems are often dealt with through devices like hearing aids that amplify incoming sound waves to make vibration of the eardrum and movement of the ossicles more likely

    166 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    to occur.

    When the hearing problem is associated with a failure to transmit neural signals from the cochlea to the brain, it is called sensorineural hearing loss. One disease that results in sensorineural hearing loss is Ménière’s disease. Although not well understood, Ménière’s disease results in a degeneration of inner ear structures that can lead to hearing loss, tinnitus (constant ringing or buzzing), vertigo (a sense of spinning), and an increase in pressure within the inner ear (Semaan & Megerian, 2011). This kind of loss cannot be treated with hearing aids, but some individuals might be candidates for a cochlear implant as a treatment option. Cochlear implants are electronic devices that consist of a microphone, a speech processor, and an electrode array. The device receives incoming sound information and directly stimulates the auditory nerve to transmit information to the brain.

    Watch this video (http://www.youtube.com/watch?v=AqXBrKwB96E) describe cochlear implant surgeries and how they work.

    Deaf Culture

    In the United States and other places around the world, deaf people have their own language, schools, and customs. This is called deaf culture. In the United States, deaf individuals often communicate using American Sign Language (ASL); ASL has no verbal component and is based entirely on visual signs and gestures. The primary mode of communication is signing. One of the values of deaf culture is to continue traditions like using sign language rather than teaching deaf children to try to speak, read lips, or have cochlear implant surgery.

    When a child is diagnosed as deaf, parents have difficult decisions to make. Should the child be enrolled in mainstream schools and taught to verbalize and read lips? Or should the child be sent to a school for deaf children to learn ASL and have significant exposure to deaf culture? Do you think there might be differences in the way that parents approach these decisions depending on whether or not they are also deaf?

    5.5 The Other Senses

    Learning Objectives

    By the end of this section, you will be able to: • Describe the basic functions of the chemical senses • Explain the basic functions of the somatosensory, nociceptive, and thermoceptive sensory

    systems • Describe the basic functions of the vestibular, proprioceptive, and kinesthetic sensory

    systems

    Vision and hearing have received an incredible amount of attention from researchers over the years. While there is still much to be learned about how these sensory systems work, we have a much better understanding of them than of our other sensory modalities. In this section, we will explore our chemical

    LINK TO LEARNING

    WHAT DO YOU THINK?

    Chapter 5 | Sensation and Perception 167

     

     

    senses (taste and smell) and our body senses (touch, temperature, pain, balance, and body position).

    THE CHEMICAL SENSES Taste (gustation) and smell (olfaction) are called chemical senses because both have sensory receptors that respond to molecules in the food we eat or in the air we breathe. There is a pronounced interaction between our chemical senses. For example, when we describe the flavor of a given food, we are really referring to both gustatory and olfactory properties of the food working in combination.

    Taste (Gustation) You have learned since elementary school that there are four basic groupings of taste: sweet, salty, sour, and bitter. Research demonstrates, however, that we have at least six taste groupings. Umami is our fifth taste. Umami is actually a Japanese word that roughly translates to yummy, and it is associated with a taste for monosodium glutamate (Kinnamon & Vandenbeuch, 2009). There is also a growing body of experimental evidence suggesting that we possess a taste for the fatty content of a given food (Mizushige, Inoue, & Fushiki, 2007).

    Molecules from the food and beverages we consume dissolve in our saliva and interact with taste receptors on our tongue and in our mouth and throat. Taste buds are formed by groupings of taste receptor cells with hair-like extensions that protrude into the central pore of the taste bud (Figure 5.19). Taste buds have a life cycle of ten days to two weeks, so even destroying some by burning your tongue won’t have any long-term effect; they just grow right back. Taste molecules bind to receptors on this extension and cause chemical changes within the sensory cell that result in neural impulses being transmitted to the brain via different nerves, depending on where the receptor is located. Taste information is transmitted to the medulla, thalamus, and limbic system, and to the gustatory cortex, which is tucked underneath the overlap between the frontal and temporal lobes (Maffei, Haley, & Fontanini, 2012; Roper, 2013).

    Figure 5.19 (a) Taste buds are composed of a number of individual taste receptors cells that transmit information to nerves. (b) This micrograph shows a close-up view of the tongue’s surface. (credit a: modification of work by Jonas Töle; credit b: scale-bar data from Matt Russell)

    Smell (Olfaction) Olfactory receptor cells are located in a mucous membrane at the top of the nose. Small hair-like extensions from these receptors serve as the sites for odor molecules dissolved in the mucus to interact with chemical receptors located on these extensions (Figure 5.20). Once an odor molecule has bound a given receptor, chemical changes within the cell result in signals being sent to the olfactory bulb: a bulb-

    168 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    like structure at the tip of the frontal lobe where the olfactory nerves begin. From the olfactory bulb, information is sent to regions of the limbic system and to the primary olfactory cortex, which is located very near the gustatory cortex (Lodovichi & Belluscio, 2012; Spors et al., 2013).

    Figure 5.20 Olfactory receptors are the hair-like parts that extend from the olfactory bulb into the mucous membrane of the nasal cavity.

    There is tremendous variation in the sensitivity of the olfactory systems of different species. We often think of dogs as having far superior olfactory systems than our own, and indeed, dogs can do some remarkable things with their noses. There is some evidence to suggest that dogs can “smell” dangerous drops in blood glucose levels as well as cancerous tumors (Wells, 2010). Dogs’ extraordinary olfactory abilities may be due to the increased number of functional genes for olfactory receptors (between 800 and 1200), compared to the fewer than 400 observed in humans and other primates (Niimura & Nei, 2007).

    Many species respond to chemical messages, known as pheromones, sent by another individual (Wysocki & Preti, 2004). Pheromonal communication often involves providing information about the reproductive status of a potential mate. So, for example, when a female rat is ready to mate, she secretes pheromonal signals that draw attention from nearby male rats. Pheromonal activation is actually an important component in eliciting sexual behavior in the male rat (Furlow, 1996, 2012; Purvis & Haynes, 1972; Sachs, 1997). There has also been a good deal of research (and controversy) about pheromones in humans (Comfort, 1971; Russell, 1976; Wolfgang-Kimball, 1992; Weller, 1998).

    TOUCH, THERMOCEPTION, AND NOCICEPTION A number of receptors are distributed throughout the skin to respond to various touch-related stimuli (Figure 5.21). These receptors include Meissner’s corpuscles, Pacinian corpuscles, Merkel’s disks, and Ruffini corpuscles. Meissner’s corpuscles respond to pressure and lower frequency vibrations, and Pacinian corpuscles detect transient pressure and higher frequency vibrations. Merkel’s disks respond to light pressure, while Ruffini corpuscles detect stretch (Abraira & Ginty, 2013).

    Chapter 5 | Sensation and Perception 169

     

     

    Figure 5.21 There are many types of sensory receptors located in the skin, each attuned to specific touch-related stimuli.

    In addition to the receptors located in the skin, there are also a number of free nerve endings that serve sensory functions. These nerve endings respond to a variety of different types of touch-related stimuli and serve as sensory receptors for both thermoception (temperature perception) and nociception (a signal indicating potential harm and maybe pain) (Garland, 2012; Petho & Reeh, 2012; Spray, 1986). Sensory information collected from the receptors and free nerve endings travels up the spinal cord and is transmitted to regions of the medulla, thalamus, and ultimately to somatosensory cortex, which is located in the postcentral gyrus of the parietal lobe.

    Pain Perception Pain is an unpleasant experience that involves both physical and psychological components. Feeling pain is quite adaptive because it makes us aware of an injury, and it motivates us to remove ourselves from the cause of that injury. In addition, pain also makes us less likely to suffer additional injury because we will be gentler with our injured body parts.

    Generally speaking, pain can be considered to be neuropathic or inflammatory in nature. Pain that signals some type of tissue damage is known as inflammatory pain. In some situations, pain results from damage to neurons of either the peripheral or central nervous system. As a result, pain signals that are sent to the brain get exaggerated. This type of pain is known as neuropathic pain. Multiple treatment options for pain relief range from relaxation therapy to the use of analgesic medications to deep brain stimulation. The most effective treatment option for a given individual will depend on a number of considerations, including the severity and persistence of the pain and any medical/psychological conditions.

    Some individuals are born without the ability to feel pain. This very rare genetic disorder is known as congenital insensitivity to pain (or congenital analgesia). While those with congenital analgesia can detect differences in temperature and pressure, they cannot experience pain. As a result, they often suffer significant injuries. Young children have serious mouth and tongue injuries because they have bitten themselves repeatedly. Not surprisingly, individuals suffering from this disorder have much shorter life expectancies due to their injuries and secondary infections of injured sites (U.S. National Library of Medicine, 2013).

    170 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    Watch this video (http://openstaxcollege.org/l/congenital) to learn more about congenital insensitivity to pain.

    THE VESTIBULAR SENSE, PROPRIOCEPTION, AND KINESTHESIA The vestibular sense contributes to our ability to maintain balance and body posture. As Figure 5.22 shows, the major sensory organs (utricle, saccule, and the three semicircular canals) of this system are located next to the cochlea in the inner ear. The vestibular organs are fluid-filled and have hair cells, similar to the ones found in the auditory system, which respond to movement of the head and gravitational forces. When these hair cells are stimulated, they send signals to the brain via the vestibular nerve. Although we may not be consciously aware of our vestibular system’s sensory information under normal circumstances, its importance is apparent when we experience motion sickness and/or dizziness related to infections of the inner ear (Khan & Chang, 2013).

    Figure 5.22 The major sensory organs of the vestibular system are located next to the cochlea in the inner ear. These include the utricle, saccule, and the three semicircular canals (posterior, superior, and horizontal).

    In addition to maintaining balance, the vestibular system collects information critical for controlling movement and the reflexes that move various parts of our bodies to compensate for changes in body position. Therefore, both proprioception (perception of body position) and kinesthesia (perception of the body’s movement through space) interact with information provided by the vestibular system.

    These sensory systems also gather information from receptors that respond to stretch and tension in muscles, joints, skin, and tendons (Lackner & DiZio, 2005; Proske, 2006; Proske & Gandevia, 2012). Proprioceptive and kinesthetic information travels to the brain via the spinal column. Several cortical regions in addition to the cerebellum receive information from and send information to the sensory organs of the proprioceptive and kinesthetic systems.

    LINK TO LEARNING

    Chapter 5 | Sensation and Perception 171

     

     

    5.6 Gestalt Principles of Perception

    Learning Objectives

    By the end of this section, you will be able to: • Explain the figure-ground relationship • Define Gestalt principles of grouping • Describe how perceptual set is influenced by an individual’s characteristics and mental state

    In the early part of the 20th century, Max Wertheimer published a paper demonstrating that individuals perceived motion in rapidly flickering static images—an insight that came to him as he used a child’s toy tachistoscope. Wertheimer, and his assistants Wolfgang Köhler and Kurt Koffka, who later became his partners, believed that perception involved more than simply combining sensory stimuli. This belief led to a new movement within the field of psychology known as Gestalt psychology. The word gestalt literally means form or pattern, but its use reflects the idea that the whole is different from the sum of its parts. In other words, the brain creates a perception that is more than simply the sum of available sensory inputs, and it does so in predictable ways. Gestalt psychologists translated these predictable ways into principles by which we organize sensory information. As a result, Gestalt psychology has been extremely influential in the area of sensation and perception (Rock & Palmer, 1990).

    One Gestalt principle is the figure-ground relationship. According to this principle, we tend to segment our visual world into figure and ground. Figure is the object or person that is the focus of the visual field, while the ground is the background. As Figure 5.23 shows, our perception can vary tremendously, depending on what is perceived as figure and what is perceived as ground. Presumably, our ability to interpret sensory information depends on what we label as figure and what we label as ground in any particular case, although this assumption has been called into question (Peterson & Gibson, 1994; Vecera & O’Reilly, 1998).

    Figure 5.23 The concept of figure-ground relationship explains why this image can be perceived either as a vase or as a pair of faces.

    Another Gestalt principle for organizing sensory stimuli into meaningful perception is proximity. This principle asserts that things that are close to one another tend to be grouped together, as Figure 5.24 illustrates.

    172 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    Figure 5.24 The Gestalt principle of proximity suggests that you see (a) one block of dots on the left side and (b) three columns on the right side.

    How we read something provides another illustration of the proximity concept. For example, we read this sentence like this, notl iket hiso rt hat. We group the letters of a given word together because there are no spaces between the letters, and we perceive words because there are spaces between each word. Here are some more examples: Cany oum akes enseo ft hiss entence? What doth es e wor dsmea n?

    We might also use the principle of similarity to group things in our visual fields. According to this principle, things that are alike tend to be grouped together (Figure 5.25). For example, when watching a football game, we tend to group individuals based on the colors of their uniforms. When watching an offensive drive, we can get a sense of the two teams simply by grouping along this dimension.

    Figure 5.25 When looking at this array of dots, we likely perceive alternating rows of colors. We are grouping these dots according to the principle of similarity.

    Two additional Gestalt principles are the law of continuity (or good continuation) and closure. The law of continuity suggests that we are more likely to perceive continuous, smooth flowing lines rather than jagged, broken lines (Figure 5.26). The principle of closure states that we organize our perceptions into complete objects rather than as a series of parts (Figure 5.27).

    Chapter 5 | Sensation and Perception 173

     

     

    Figure 5.26 Good continuation would suggest that we are more likely to perceive this as two overlapping lines, rather than four lines meeting in the center.

    Figure 5.27 Closure suggests that we will perceive a complete circle and rectangle rather than a series of segments.

    Watch this video (http://openstaxcollege.org/l/gestalt) showing real world illustrations of Gestalt principles.

    According to Gestalt theorists, pattern perception, or our ability to discriminate among different figures and shapes, occurs by following the principles described above. You probably feel fairly certain that your perception accurately matches the real world, but this is not always the case. Our perceptions are based on perceptual hypotheses: educated guesses that we make while interpreting sensory information. These hypotheses are informed by a number of factors, including our personalities, experiences, and expectations. We use these hypotheses to generate our perceptual set. For instance, research has demonstrated that those who are given verbal priming produce a biased interpretation of complex ambiguous figures (Goolkasian & Woodbury, 2010).

    LINK TO LEARNING

    174 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    The Depths of Perception: Bias, Prejudice, and Cultural Factors

    In this chapter, you have learned that perception is a complex process. Built from sensations, but influenced by our own experiences, biases, prejudices, and cultures, perceptions can be very different from person to person. Research suggests that implicit racial prejudice and stereotypes affect perception. For instance, several studies have demonstrated that non-Black participants identify weapons faster and are more likely to identify non-weapons as weapons when the image of the weapon is paired with the image of a Black person (Payne, 2001; Payne, Shimizu, & Jacoby, 2005). Furthermore, White individuals’ decisions to shoot an armed target in a video game is made more quickly when the target is Black (Correll, Park, Judd, & Wittenbrink, 2002; Correll, Urland, & Ito, 2006). This research is important, considering the number of very high-profile cases in the last few decades in which young Blacks were killed by people who claimed to believe that the unarmed individuals were armed and/or represented some threat to their personal safety.

    DIG DEEPER

    Chapter 5 | Sensation and Perception 175

     

     

    absolute threshold

    afterimage

    amplitude

    basilar membrane

    binaural cue

    binocular cue

    binocular disparity

    blind spot

    bottom-up processing

    closure

    cochlea

    cochlear implant

    conductive hearing loss

    cone

    congenital deafness

    congenital insensitivity to pain (congenital analgesia)

    cornea

    deafness

    decibel (dB)

    depth perception

    electromagnetic spectrum

    figure-ground relationship

    fovea

    frequency

    Gestalt psychology

    good continuation

    Key Terms

    minimum amount of stimulus energy that must be present for the stimulus to be detected 50% of the time

    continuation of a visual sensation after removal of the stimulus

    height of a wave

    thin strip of tissue within the cochlea that contains the hair cells which serve as the sensory receptors for the auditory system

    two-eared cue to localize sound

    cue that relies on the use of both eyes

    slightly different view of the world that each eye receives

    point where we cannot respond to visual information in that portion of the visual field

    system in which perceptions are built from sensory input

    organizing our perceptions into complete objects rather than as a series of parts

    fluid-filled, snail-shaped structure that contains the sensory receptor cells of the auditory system

    electronic device that consists of a microphone, a speech processor, and an electrode array to directly stimulate the auditory nerve to transmit information to the brain

    failure in the vibration of the eardrum and/or movement of the ossicles

    specialized photoreceptor that works best in bright light conditions and detects color

    deafness from birth

    genetic disorder that results in the inability to experience pain

    transparent covering over the eye

    partial or complete inability to hear

    logarithmic unit of sound intensity

    ability to perceive depth

    all the electromagnetic radiation that occurs in our environment

    segmenting our visual world into figure and ground

    small indentation in the retina that contains cones

    number of waves that pass a given point in a given time period

    field of psychology based on the idea that the whole is different from the sum of its parts

    (also, continuity) we are more likely to perceive continuous, smooth flowing lines

    176 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    hair cell

    hertz (Hz)

    inattentional blindness

    incus

    inflammatory pain

    interaural level difference

    interaural timing difference

    iris

    just noticeable difference

    kinesthesia

    lens

    linear perspective

    malleus

    Meissner’s corpuscle

    Merkel’s disk

    monaural cue

    monocular cue

    Ménière’s disease

    neuropathic pain

    nociception

    olfactory bulb

    olfactory receptor

    opponent-process theory of color perception

    optic chiasm

    optic nerve

    Pacinian corpuscle

    rather than jagged, broken lines

    auditory receptor cell of the inner ear

    cycles per second; measure of frequency

    failure to notice something that is completely visible because of a lack of attention

    middle ear ossicle; also known as the anvil

    signal that some type of tissue damage has occurred

    sound coming from one side of the body is more intense at the closest ear because of the attenuation of the sound wave as it passes through the head

    small difference in the time at which a given sound wave arrives at each ear

    colored portion of the eye

    difference in stimuli required to detect a difference between the stimuli

    perception of the body’s movement through space

    curved, transparent structure that provides additional focus for light entering the eye

    perceive depth in an image when two parallel lines seem to converge

    middle ear ossicle; also known as the hammer

    touch receptor that responds to pressure and lower frequency vibrations

    touch receptor that responds to light touch

    one-eared cue to localize sound

    cue that requires only one eye

    results in a degeneration of inner ear structures that can lead to hearing loss, tinnitus, vertigo, and an increase in pressure within the inner ear

    pain from damage to neurons of either the peripheral or central nervous system

    sensory signal indicating potential harm and maybe pain

    bulb-like structure at the tip of the frontal lobe, where the olfactory nerves begin

    sensory cell for the olfactory system

    color is coded in opponent pairs: black-white, yellow-blue, and red-green

    X-shaped structure that sits just below the brain’s ventral surface; represents the merging of the optic nerves from the two eyes and the separation of information from the two sides of the visual field to the opposite side of the brain

    carries visual information from the retina to the brain

    touch receptor that detects transient pressure and higher frequency vibrations

    Chapter 5 | Sensation and Perception 177

     

     

    pattern perception

    peak

    perception

    perceptual hypothesis

    pheromone

    photoreceptor

    pinna

    pitch

    place theory of pitch perception

    principle of closure

    proprioception

    proximity

    pupil

    retina

    rod

    Ruffini corpuscle

    sensation

    sensorineural hearing loss

    sensory adaptation

    signal detection theory

    similarity

    stapes

    subliminal message

    taste bud

    temporal theory of pitch perception

    thermoception

    timbre

    top-down processing

    ability to discriminate among different figures and shapes

    (also, crest) highest point of a wave

    way that sensory information is interpreted and consciously experienced

    educated guess used to interpret sensory information

    chemical message sent by another individual

    light-detecting cell

    visible part of the ear that protrudes from the head

    perception of a sound’s frequency

    different portions of the basilar membrane are sensitive to sounds of different frequencies

    organize perceptions into complete objects rather than as a series of parts

    perception of body position

    things that are close to one another tend to be grouped together

    small opening in the eye through which light passes

    light-sensitive lining of the eye

    specialized photoreceptor that works well in low light conditions

    touch receptor that detects stretch

    what happens when sensory information is detected by a sensory receptor

    failure to transmit neural signals from the cochlea to the brain

    not perceiving stimuli that remain relatively constant over prolonged periods of time

    change in stimulus detection as a function of current mental state

    things that are alike tend to be grouped together

    middle ear ossicle; also known as the stirrup

    message presented below the threshold of conscious awareness

    grouping of taste receptor cells with hair-like extensions that protrude into the central pore of the taste bud

    sound’s frequency is coded by the activity level of a sensory neuron

    temperature perception

    sound’s purity

    interpretation of sensations is influenced by available knowledge, experiences, and thoughts

    178 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    transduction

    trichromatic theory of color perception

    trough

    tympanic membrane

    umami

    vertigo

    vestibular sense

    visible spectrum

    wavelength

    conversion from sensory stimulus energy to action potential

    color vision is mediated by the activity across the three groups of cones

    lowest point of a wave

    eardrum

    taste for monosodium glutamate

    spinning sensation

    contributes to our ability to maintain balance and body posture

    portion of the electromagnetic spectrum that we can see

    length of a wave from one peak to the next peak

    Summary

    5.1 Sensation versus Perception Sensation occurs when sensory receptors detect sensory stimuli. Perception involves the organization, interpretation, and conscious experience of those sensations. All sensory systems have both absolute and difference thresholds, which refer to the minimum amount of stimulus energy or the minimum amount of difference in stimulus energy required to be detected about 50% of the time, respectively. Sensory adaptation, selective attention, and signal detection theory can help explain what is perceived and what is not. In addition, our perceptions are affected by a number of factors, including beliefs, values, prejudices, culture, and life experiences.

    5.2 Waves and Wavelengths Both light and sound can be described in terms of wave forms with physical characteristics like amplitude, wavelength, and timbre. Wavelength and frequency are inversely related so that longer waves have lower frequencies, and shorter waves have higher frequencies. In the visual system, a light wave’s wavelength is generally associated with color, and its amplitude is associated with brightness. In the auditory system, a sound’s frequency is associated with pitch, and its amplitude is associated with loudness.

    5.3 Vision Light waves cross the cornea and enter the eye at the pupil. The eye’s lens focuses this light so that the image is focused on a region of the retina known as the fovea. The fovea contains cones that possess high levels of visual acuity and operate best in bright light conditions. Rods are located throughout the retina and operate best under dim light conditions. Visual information leaves the eye via the optic nerve. Information from each visual field is sent to the opposite side of the brain at the optic chiasm. Visual information then moves through a number of brain sites before reaching the occipital lobe, where it is processed.

    Two theories explain color perception. The trichromatic theory asserts that three distinct cone groups are tuned to slightly different wavelengths of light, and it is the combination of activity across these cone types that results in our perception of all the colors we see. The opponent-process theory of color vision asserts that color is processed in opponent pairs and accounts for the interesting phenomenon of a negative afterimage. We perceive depth through a combination of monocular and binocular depth cues.

    5.4 Hearing Sound waves are funneled into the auditory canal and cause vibrations of the eardrum; these vibrations move the ossicles. As the ossicles move, the stapes presses against the oval window of the cochlea, which

    Chapter 5 | Sensation and Perception 179

     

     

    causes fluid inside the cochlea to move. As a result, hair cells embedded in the basilar membrane become enlarged, which sends neural impulses to the brain via the auditory nerve.

    Pitch perception and sound localization are important aspects of hearing. Our ability to perceive pitch relies on both the firing rate of the hair cells in the basilar membrane as well as their location within the membrane. In terms of sound localization, both monaural and binaural cues are used to locate where sounds originate in our environment.

    Individuals can be born deaf, or they can develop deafness as a result of age, genetic predisposition, and/ or environmental causes. Hearing loss that results from a failure of the vibration of the eardrum or the resultant movement of the ossicles is called conductive hearing loss. Hearing loss that involves a failure of the transmission of auditory nerve impulses to the brain is called sensorineural hearing loss.

    5.5 The Other Senses Taste (gustation) and smell (olfaction) are chemical senses that employ receptors on the tongue and in the nose that bind directly with taste and odor molecules in order to transmit information to the brain for processing. Our ability to perceive touch, temperature, and pain is mediated by a number of receptors and free nerve endings that are distributed throughout the skin and various tissues of the body. The vestibular sense helps us maintain a sense of balance through the response of hair cells in the utricle, saccule, and semi-circular canals that respond to changes in head position and gravity. Our proprioceptive and kinesthetic systems provide information about body position and body movement through receptors that detect stretch and tension in the muscles, joints, tendons, and skin of the body.

    5.6 Gestalt Principles of Perception Gestalt theorists have been incredibly influential in the areas of sensation and perception. Gestalt principles such as figure-ground relationship, grouping by proximity or similarity, the law of good continuation, and closure are all used to help explain how we organize sensory information. Our perceptions are not infallible, and they can be influenced by bias, prejudice, and other factors.

    Review Questions

    1. ________ refers to the minimum amount of stimulus energy required to be detected 50% of the time.

    a. absolute threshold b. difference threshold c. just noticeable difference d. transduction

    2. Decreased sensitivity to an unchanging stimulus is known as ________.

    a. transduction b. difference threshold c. sensory adaptation d. inattentional blindness

    3. ________ involves the conversion of sensory stimulus energy into neural impulses.

    a. sensory adaptation b. inattentional blindness c. difference threshold d. transduction

    4. ________ occurs when sensory information is organized, interpreted, and consciously experienced.

    a. sensation b. perception c. transduction d. sensory adaptation

    5. Which of the following correctly matches the pattern in our perception of color as we move from short wavelengths to long wavelengths?

    a. red to orange to yellow b. yellow to orange to red c. yellow to red to orange d. orange to yellow to red

    6. The visible spectrum includes light that ranges from about ________.

    a. 400–700 nm b. 200–900 nm c. 20–20000 Hz d. 10–20 dB

    180 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    7. The electromagnetic spectrum includes ________.

    a. radio waves b. x-rays c. infrared light d. all of the above

    8. The audible range for humans is ________. a. 380–740 Hz b. 10–20 dB c. less than 300 dB d. 20-20,000 Hz

    9. The quality of a sound that is affected by frequency, amplitude, and timing of the sound wave is known as ________.

    a. pitch b. tone c. electromagnetic d. timbre

    10. The ________ is a small indentation of the retina that contains cones.

    a. optic chiasm b. optic nerve c. fovea d. iris

    11. ________ operate best under bright light conditions.

    a. cones b. rods c. retinal ganglion cells d. striate cortex

    12. ________ depth cues require the use of both eyes.

    a. monocular b. binocular c. linear perspective d. accommodating

    13. If you were to stare at a green dot for a relatively long period of time and then shift your gaze to a blank white screen, you would see a ________ negative afterimage.

    a. blue b. yellow c. black d. red

    14. Hair cells located near the base of the basilar membrane respond best to ________ sounds.

    a. low-frequency b. high-frequency c. low-amplitude d. high-amplitude

    15. The three ossicles of the middle ear are known as ________.

    a. malleus, incus, and stapes b. hammer, anvil, and stirrup c. pinna, cochlea, and utricle d. both a and b

    16. Hearing aids might be effective for treating ________.

    a. Ménière’s disease b. sensorineural hearing loss c. conductive hearing loss d. interaural time differences

    17. Cues that require two ears are referred to as ________ cues.

    a. monocular b. monaural c. binocular d. binaural

    18. Chemical messages often sent between two members of a species to communicate something about reproductive status are called ________.

    a. hormones b. pheromones c. Merkel’s disks d. Meissner’s corpuscles

    19. Which taste is associated with monosodium glutamate?

    a. sweet b. bitter c. umami d. sour

    20. ________ serve as sensory receptors for temperature and pain stimuli.

    a. free nerve endings b. Pacinian corpuscles c. Ruffini corpuscles d. Meissner’s corpuscles

    Chapter 5 | Sensation and Perception 181

     

     

    21. Which of the following is involved in maintaining balance and body posture?

    a. auditory nerve b. nociceptors c. olfactory bulb d. vestibular system

    22. According to the principle of ________, objects that occur close to one another tend to be grouped together.

    a. similarity b. good continuation c. proximity d. closure

    23. Our tendency to perceive things as complete objects rather than as a series of parts is known as the principle of ________.

    a. closure b. good continuation c. proximity d. similarity

    24. According to the law of ________, we are more likely to perceive smoothly flowing lines rather than choppy or jagged lines.

    a. closure b. good continuation c. proximity d. similarity

    25. The main point of focus in a visual display is known as the ________.

    a. closure b. perceptual set c. ground d. figure

    Critical Thinking Questions

    26. Not everything that is sensed is perceived. Do you think there could ever be a case where something could be perceived without being sensed?

    27. Please generate a novel example of how just noticeable difference can change as a function of stimulus intensity.

    28. Why do you think other species have such different ranges of sensitivity for both visual and auditory stimuli compared to humans?

    29. Why do you think humans are especially sensitive to sounds with frequencies that fall in the middle portion of the audible range?

    30. Compare the two theories of color perception. Are they completely different?

    31. Color is not a physical property of our environment. What function (if any) do you think color vision serves?

    32. Given what you’ve read about sound localization, from an evolutionary perspective, how does sound localization facilitate survival?

    33. How can temporal and place theories both be used to explain our ability to perceive the pitch of sound waves with frequencies up to 4000 Hz?

    34. Many people experience nausea while traveling in a car, plane, or boat. How might you explain this as a function of sensory interaction?

    182 Chapter 5 | Sensation and Perception

    This OpenStax book is available for free at https://cnx.org/content/col11629/1.5

     

     

    35. If you heard someone say that they would do anything not to feel the pain associated with significant injury, how would you respond given what you’ve just read?

    36. Do you think women experience pain differently than men? Why do you think this is?

    37. The central tenet of Gestalt psychology is that the whole is different from the sum of its parts. What does this mean in the context of perception?

    38. Take a look at the following figure. How might you influence whether people see a duck or a rabbit?

    Figure 5.28

    Personal Application Questions

    39. Think about a time when you failed to notice something around you because your attention was focused elsewhere. If someone pointed it out, were you surprised that you hadn’t noticed it right away?

    40. If you grew up with a family pet, then you have surely noticed that they often seem to hear things that you don’t hear. Now that you’ve read this section, you probably have some insight as to why this may be. How would you explain this to a friend who never had the opportunity to take a class like this?

    41. Take a look at a few of your photos or personal works of art. Can you find examples of linear perspective as a potential depth cue?

    42. If you had to choose to lose either your vision or your hearing, which would you choose and why?

    43. As mentioned earlier, a food’s flavor represents an interaction of both gustatory and olfactory information. Think about the last time you were seriously congested due to a cold or the flu. What changes did you notice in the flavors of the foods that you ate during this time?

    44. Have you ever listened to a song on the radio and sung along only to find out later that you have been singing the wrong lyrics? Once you found the correct lyrics, did your perception of the song change?

    Chapter 5 | Sensation and Perception 183

Bipolar And Depressive Disorders Comparison Chart

Directions: Although bipolar and depressive disorders share several key similarities, some aspects are radically different among these disorders. The completion of this chart gives you an opportunity to thoroughly compare and contrast these specific disorders. Complete the table below by following the example provided for Cyclothymic Disorder. Include examples and at least two scholarly

cid:D7D4B297-EEAE-4174-AD01-F87097282051@canyon.com

 

PCN-605 Topic 4: Bipolar and Depressive Disorders Comparison Chart

Directions: Although bipolar and depressive disorders share several key similarities, some aspects are radically different among these disorders. The completion of this chart gives you an opportunity to thoroughly compare and contrast these specific disorders. Complete the table below by following the example provided for Cyclothymic Disorder. Include examples and at least two scholarly references as reference notes below the chart.

Note: “D/O” is an acronym for disorder

Disorder and Features Depressive Episode? Manic Episode? Hypomanic Episode? Duration of Clinically-Significant Symptoms Duration of Symptom-Free Intervals Distinguish From (Differential Diagnosis): Comorbidity (Often Seen With):
Cyclothymic Disorder No, but episodes only that do not meet full criteria No No, but episodes only that do not meet full criteria 2+ yr. in Adults

1+ yr. in Adolescents

No longer than 2 months Psychotic D/O

Bipolar D/O

Borderline PD

Substance-Induced D/O

Substance-Related D/O

Sleep D/O

ADHD

MDD

Major Depressive Disorder

 

 

 

           
Dysthymia Persistent Depressive Disorder              
DMDD

Disruptive Mood Dysregulation Disorder

             
Bipolar I Disorder

 

             
Bipolar II Disorder

 

             

 

 

References

© 2019. Grand Canyon University. All Rights Reserved.

© 2019. Grand Canyon University. All Rights Reserved.