Schram, Introduction to Criminology

Chapter 5

Modern Biosocial Perspectives on Criminal Behavior

Summary This chapter discussed the early studies that explored the relative influence of nature versus nurture, such as the early family studies, as well as the more robust subsequent wave of twin studies, adoption studies, and studies of identical twins who were raised apart. Family studies were conducted to determine if criminality was more likely to be found in a given family. The results of the family studies determined that criminality is indeed more common in some families and the criminality by the mother (or head female caretaker) had a much stronger influence on the future criminality of the children than the father’s criminality. Twin studies were specifically designed to determine the relative influence between nature and nurture. It would be expected, that identical twins (MZ twins) would have higher concordance rates than fraternal twins (DZ twins). Adoption studies examined the predictive influence of the biological parents of adopted children versus that of the adoptive parents that raised the children from infancy to adulthood. The adoption studies revealed that the highest predictability for future criminality was found for adopted youth who had both biological and adoptive parents who were convicted criminals. Finally, twins separated at birth studies determined that twin pairs often showed extremely similar tendencies for criminality, sometimes more than those seen in concordance rates for identical twins raised together. Overall, these studies revealed not only an answer to the nature versus nurture argument, but also revealed that it is “nature via nurture” that should be emphasized when it comes to predicting criminality. The second issue discussed in the chapter is the influence of hormones (e.g., testosterone) and neurotransmitters in human behavior, as well as the influence of variations in chromosomal mutations (e.g., XYY). Although hormones are a key part of the criminal process, they probably are secondary in terms of levels of neurotransmitters. The key neurotransmitters are dopamine and serotonin. In reference to dopamine, there is a curvilinear relationship between it and criminal behavior, such that both extremely high and extremely low levels are both associated with deviance. However, in relation to serotonin, the research has consistently shown that it is low levels of this neurotransmitter that is linked with criminal offending. Recent research has supported both of these theories in showing that persons with high levels of male androgens are more likely to commit crime than those who do not have high levels of these hormones. The link between brain trauma was also discussed, with an emphasis on the consistent association between damage to the left and/or frontal parts of the brain. The chapter also examined theories regarding variations in levels of functioning of the central nervous system (CNS) and the autonomic nervous system (ANS), and all empirical studies have shown that low levels of functioning of these systems have links to criminality. Next, biosocial approaches are examined. This approach has clearly shown that it is the interaction between biological factors and environmental deficiencies that are the most consistent in predicting criminality. The chapter concluded with the discussion of how diet and nutrition, as well as exposure to dangerous toxins affect criminal behavior. In relation to diet and nutrition, studies have shown a correlation between the reduction of simple carbohydrates and lower levels of violations by incarcerated juveniles. High levels of certain toxins, particularly lead and manganese, can have a profound effect on behavior, including criminality. Ultimately, it is interesting that the very theories that were key in the early years of development of criminology as a science, such as brain

 

 

Schram, Introduction to Criminology structure/functioning and other early diagnostics from the first year(s) of life (e.g., Apgar scores), are now showing strong support in studies as being a primary influence on criminal behavior. ! Conclusion

Theory Key Proponents Concepts/Factors Key Propositions

Family Studies Dugdale, Goddard, etc.

Criminality Criminality runs in families.

Twin Studies Various Concordance for criminality

MZ twins have higher concordance than DZ twins.

Adoption Studies Mednick & Colleagues and many others

Criminality among various adoptees

Adoptees with criminal biological parents more likely to be criminal, as compared to criminal adoptive parents.

MZ Twins Separated at Birth

Various Concordance rates of MZ twins raised apart

Criminality among MZ twins reared apart is similar.

Cytogenetic Studies Jacobs, and many others

Chromosomal mutations

XYY individuals have more criminality.

Hormonal Theory Various Testosterone, estrogen levels

Higher levels of testosterone and lower levels of estrogen predict criminality.

Neurotransmitters Various Dopamine, Serotonin, etc.

Low levels of serotonin predict more criminality, whereas findings for other neurotransmitters are mixed.

Brain Injury Various Various lobes and brain structures

Trauma to certain portions of the brain (e.g., frontal lobe) and structures (e.g., limbic structures) predict criminality.

Central Nervous System (CNS) Functioning

Various Brain wave patterns Slower brain wave patterns predict criminality.

Autonomic Nervous System (ANS) Functioning

Various Heart rate, sweating, and other indicators

Lower ANS functioning predicts criminality.

 

 

Schram, Introduction to Criminology Biosocial Interaction Theory

Various A variety of both physiological and developmental factors

Weak physiological factors interact with weak social and environmental factors to predict criminality.