Discuss how the research method used in the article addresses intrinsic and extrinsic motivation.

The Behavior Analyst 2001, 24, 1-44 No. 1 (Spring)

Pervasive Negative Effects of Rewards on Intrinsic Motivation:

The Myth Continues Judy Cameron, Katherine M. Banko,

and W; David Pierce University of Alberta

A major concern in psychology and education is that rewards decrease intrinsic motivation to perform activities. Over the past 30 years, more than 100 experimental studies have been conducted on this topic. In 1994, Cameron and Pierce conducted a meta-analysis of this literature and con- cluded that negative effects of reward were limited and could be easily prevented in applied settings. A more recent meta-analysis of the literature by Deci, Koestner, and Ryan (1999) shows pervasive negative effects of reward. The purpose of the present article is to resolve differences in previous meta-analytic findings and to provide a meta-analysis of rewards and intrinsic motivation that per- mits tests of competing theoretical explanations. Our results suggest that in general, rewards are not harmful to motivation to perform a task. Rewards given for low-interest tasks enhance free-choice intrinsic motivation. On high-interest tasks, verbal rewards produce positive effects on free-choice motivation and self-reported task interest. Negative effects are found on high-interest tasks when the rewards are tangible, expected (offered beforehand), and loosely tied to level of performance. When rewards are linked to level of performance, measures of intrinsic motivation increase or do not differ from a nonrewarded control group. Overall, the pattern of results indicates that reward contingencies do not have pervasive negative effects on intrinsic motivation. Theoretical and prac- tical implications of the findings are addressed. Key words: meta-analysis, rewards, reinforcement, intrinsic motivation, intrinsic interest

Most parents, educators, and behav- ior analysts would agree that the ideal student is one who performs academic tasks at a high level, shows high inter- est and involvement in school activi- ties, is willing to take on challenging assignments, and is a self-motivated learner. To instill interest and to height- en student performance, many practi- tioners implement reward and incen- tive systems in educational settings. In recent years, the wisdom of this prac- tice has been debated in literature re- views, textbooks, and the popular me- dia. Many writers and researchers claim that giving students high grades, prizes, money, and even praise for en- gaging in an activity may be effective in getting students to perform a task,

This work, was supported by a research grant from the Social Sciences and Humanities Re- search Council of Canada.

Correspondence concerning this article should be addressed to Judy Cameron, Department of Educational Psychology, 6-102 Education North, University of Alberta, Edmonton, Alber- ta, T6G 2G5 Canada.

but performance and interest are main- tained only as long as the rewards keep coming. In other words, rewards are said to undermine intrinsic motivation. This premise is based on the view that when individuals like what they are doing, they experience feelings of competence and self-determination. When students are given a reward for performance, the claim is that they be- gin to do the activity for the external reward rather than for intrinsic reasons. As a result, perceptions of competence and self-determination are said to de- crease and motivation to perform the activity declines.

Those who decry the use of rewards support their position by citing exper- imental studies on rewards and intrin- sic motivation conducted in social psy- chology and education. Since the 1970s, dozens of experiments have been designed to assess the impact of rewards on intrinsic motivation. A cur- sory examination of the studies, how- ever, reveals a mixed set of findings. That is, in some studies, extrinsic re-

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wards produce negative effects on measures of intrinsic motivation. Other studies find positive effects of reward; still others show no effect. A number of reviewers have noted the contradic- tory nature of the findings and have at- tempted to identify the conditions un- der which extrinsic rewards produce decrements on measures of intrinsic motivation (Bates, 1979; Bernstein, 1990; Carton, 1996; Dickinson, 1989; Flora, 1990; Morgan, 1984).

In 1994, Cameron and Pierce pub- lished a meta-analysis of 96 experi- mental studies on the topic (with ad- ditional analyses by Eisenberger & Cameron, 1996). Based on their re- sults, they argued that negative effects of reward were minimal and could be easily prevented in applied settings. The research and recommendations made by Cameron and Pierce and by Eisenberger and Cameron generated considerable debate (Hennessey & Amabile, 1998; Kohn, 1996; Lepper, 1998; Lepper, Keavney, & Drake, 1996; Ryan & Deci, 1996; Sansone & Harackiewicz, 1998) and seemingly spurred the publication of a new meta- analysis on the topic. Deci, Koestner, and Ryan (1999) presented a meta- analysis that claimed to support the view that rewards have pervasive neg- ative effects on intrinsic motivation.

Deci et al. (1999) identified 128 ex- periments on rewards and intrinsic mo- tivation, including 20 unpublished studies from doctoral dissertations. They outlined a number of concerns they had with the meta-analyses con- ducted by Cameron and Pierce (1994) and Eisenberger and Cameron (1996). Deci et al.’s meta-analysis was de- signed to rectify these concerns, to test cognitive evaluation theory, and to provide a more comprehensive review of the literature. Their findings sup- ported cognitive evaluation theory and, in general, rewards were found to have a substantial negative effect on intrin- sic motivation. Deci et al. concluded that “although rewards can control people’s behavior-indeed, that is pre- sumably why they are so widely ad-

vocated-the primary negative effect of rewards is that they tend to forestall self-regulation” (p. 659). The assertion that rewards decrease

intrinsic motivation has captured the attention of cognitive researchers, practitioners, and the general public because such a claim (a) seems to offer an empirical basis for psychological theories that assume that self-determi- nation and freedom from control are fundamental human motives, (b) ap- pears to question basic behavioral con- ceptions of human nature, and (c) sug- gests that rewards used in schools, hos- pitals, the workplace, and so on are more harmful than beneficial. A re- viewer of this manuscript suggested that the claim that rewards are harmful may be attractive to some practitioners and educators because detecting and rewarding performance improvements is hard work and the negative effect claim relieves us of a difficult and de- manding task.

Clearly, Deci et al.’s (1999) finding of general negative effects of reward has important theoretical and practical implications and calls for a careful analysis of contradictory empirical claims. In this article, we argue that pervasive negative effects of reward are not a necessary outcome of a meta- analysis of this literature. We contend that a careful examination of Deci et al.’s meta-analysis reveals several con- ceptual and methodological shortcom- ings. The disparate conclusions of the two major meta-analyses on the effects of reward on intrinsic motivation (Cameron & Pierce, 1994; Deci et al.) suggest the value of correcting the flaws in each and building on their strengths to draw more definitive con- clusions. In this article, we offer a re- analysis of the-effects of rewards on intrinsic motivation. Our reanalysis is informed by a consideration of Deci et al.’s decisions and procedures. In ad- dition, the concerns raised by Deci et al. about our previous research are ad- dressed. The purpose of the present ar- ticle is to resolve differences in previ- ous meta-analytic findings and to pro-

THE MYTH CONTINUES 3

vide a meta-analysis of rewards and in- trinsic motivation that permits tests of competing theoretical explanations. We begin with a general description

of the experiments conducted on re- wards and intrinsic motivation. This is followed by a brief description of the procedure and logic of meta-analysis. The meta-analyses by Cameron and Pierce (1994), Eisenberger and Cam- eron (1996), and Deci et al. (1999) are described, and criticisms of each are presented. We then provide a detailed account of how our reanalysis is de- signed to resolve differences between Deci et al.’s and our earlier reviews of this literature. Results of our new meta-analysis are presented, and dif- ferences between our findings and pre- vious reviews are explained. Finally, our discussion focuses on theoretical and practical implications of the find- ings.

THIRTY YEARS OF RESEARCH ON REWARDS

AND INTRINSIC MOTIVATION

The term intrinsic motivation is gen- erally understood in contrast to extrin- sic motivation. Intrinsically motivated behaviors are those in which there is no apparent reward except with the ac- tivity itself (Deci, 1975). Extrinsic mo- tivation, on the other hand, is said to occur when an activity is rewarded by incentives not inherent in the task. Al- though these terms have been criticized and debated (e.g., Bandura, 1986; Dickinson, 1989; Flora, 1990), they are accepted by many researchers. The dis- tinction between intrinsic and extrinsic motivation led psychologists to specu- late about the relation between these two sources. One view was that intrin- sic and extrinsic motivation combined in an additive fashion to produce over- all motivation. For example, in work settings, organizational psychologists argued that optimal performance would occur when jobs were interest- ing and challenging and employees were externally rewarded (e.g., with

money) for their work (Porter & Law- ler, 1968; Vroom, 1964). Other theo- rists challenged the additive assump- tion, suggesting instead that extrinsic rewards might interfere with intrinsic motivation (DeCharms, 1968). The idea that extrinsic rewards could

disrupt intrinsic motivation instigated a series of experiments carried out in the early 1970s (Deci, 1971; Lepper, Greene, & Nisbett, 1973). In the initial studies, researchers tested the hypoth- esis that external rewards would un- dermine intrinsic motivation either by subverting feelings of competence and self-determination or by deflecting the source of motivation from internal to external causes. Intrinsic motivation was inferred from changes in time spent on an activity once rewards were removed, performance during the non- rewarded phase, or expressed task in- terest. When rewards were found to lower time on task, performance, or in- terest, the researchers claimed that re- wards undermined intrinsic motivation. Results from the early studies appeared to offer some support for the under- mining hypothesis. That is, when in- dividuals were promised a material re- ward, their performance, time on task, and interest decreased once the reward was no longer forthcoming. Because of the implications for education, busi- ness, and the psychology of motiva- tion, the early findings led to a great deal of research on the topic.

Since the 1970s, over 100 experi- ments have been performed to inves- tigate alleged undermining effects of rewards. The vast majority of the stud- ies on rewards and intrinsic motivation have been conducted using a between- groups design. In a typical study, par- ticipants are presented with an inter- esting task (e.g., solving and assem- bling puzzles, drawing with magic markers, playing word games). Partic- ipants are rewarded with money or grades, candy, praise, good-player cer- tificates, and so forth for performing the activity. Rewards are tangible (e.g., money, candy, gold stars) or verbal (e.g., praise, approval, positive feed-

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back). In addition, the rewards may be offered beforehand (expected reward) or presented unexpectedly after the ac- tivity (unexpected reward). In some ex- periments, reward is offered simply for doing an activity; in other studies the rewards are given for completing a task or for each puzzle or unit solved. In a number of experiments, the rewards are offered for meeting or exceeding a specific standard. Participants in a con- trol condition engage in the activity without receiving a reward. The reward intervention is usually

conducted over a 10-min to 1-hr peri- od. Rewarded and nonrewarded groups are then observed during a nonreward period (typically, 2 min to 1 hr) in which participants are free to continue performing the target task or to engage in some alternative activity. The time participants spend on the target activity during this nonreward phase, their per- formance on the task during the free- choice period, or self-reported task in- terest are used as measures of intrinsic motivation. If rewarded participants spend less free time on the activity, perform at a lower level, or express less task interest than nonrewarded participants, reward is said to under- mine intrinsic motivation. The findings from the studies on re-

wards and intrinsic motivation have been diverse (positive, negative, and no effects have been reported). None- theless, the results from these studies are often cited as evidence that rewards and positive reinforcement can backfire (e.g., Kohn, 1993). External rewards are said to be controlling and to inter- fere with a basic human desire for self- determination.

Because the detrimental effects of rewards have been interpreted as a challenge to behavioral conceptions of human nature and to the benefits of be- havioral technology for education and business, a few behaviorally oriented researchers have used single-subject designs to assess the generality of the findings. In this type of study, partici- pants serve as their own controls. Mea- sures such as time on task are taken