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Introduced by psychologist Daryl J. Bem in 1965 the theory suggests that people infer their own attitudes, opinions, and other internal states partly by observing their behavior and the circumstances in which that behavior occurs. An example is of a man who is asked whether he likes brown bread and who replies, ‘I must like it; I'm always eating it’. This would be the same response that his wife would give if she were asked to answer for him. According to the theory, introspection is a poor guide to one's internal states, because internal cues are weak and ambiguous, and a person is in the same position as an outside observer, who relies on outward behavior in interpreting another's internal states.
Experiment Evidence for the Theory
The facial feedback experiment
The facial feedback hypothesis states that facial movement can influence emotional experience. For example, an individual who is forced to smile during a social event will actually find the event more enjoyable. In one study (Strack, Martin, & Stepper, 1988) participants were asked to hold a pencil in their mouth to either facilitate or inhibit smiles while rating cartoons. Participants who displayed smiles reported more positive experience when pleasant scenes and humorous cartoons were presented. These results support the facial feedback hypothesis
The False confession experiment
College subjects participated in experimental sessions disguised as research on lie detection. After crossing out specified words on a word list, each subject was trained to say true statements in the presence of a truth light and false statement in the presence of a lie light. They were then told to state aloud that they had previously crossed out certain words and had not crossed out others. Half of these confessions were false, and each was made in the presence of 1 of the 2 lights. As predicted, false confessions in the truth light produced more errors of recall and less confidence in recall accuracy than either false confessions in the lie light or no confession at all.
Other self perception phenomena
Along with the experiments there are other effects which aide in explaining and understanding self-perception theory.
Intrinsic vs. extrinsic motivation
Intrinsic motivation refers to motivation that comes from inside an individual rather than from any external or outside rewards, such as money or grades. The motivation comes from the pleasure one gets from the task itself or from the sense of satisfaction in completing or even working on a task. An intrinsically motivated person will work on a math equation, for example, because it is enjoyable.
Extrinsic motivation refers to motivation that comes from outside an individual. The motivating factors are external, or outside, rewards such as money or grades. These rewards provide satisfaction and pleasure that the task itself may not provide. An extrinsically motivated person will work on a task even when they have little interest in it because of the anticipated satisfaction they will get from some reward. The rewards can be something as minor as a smiley face to something major like fame or fortune. For example, an extrinsically motivated person who dislikes math may work hard on a math equation because they want the reward for completing it.
Overjustication occurs where people attribute their behavior more to a extrinsic motivator than to intrinsic reasons. This effect is less when rewards are given for performance success rather than simply completing tasks, but can still be significant. Greene, Sternberg and Lepper (1976) played mathematical games with schoolchildren, which the children seemed to enjoy. After a while, they started giving rewards for success. When they took away the rewards, the children quickly gave up playing the games. The explanation was that the children had decided that they were playing for the reward, not for the fun. When professional basketball players were asked why they play the sport they replied because of the money and some stated that when they began to play professionally the game seemed to loose it’s luster.
Self-Perception Theory provides an alternative explanation for cognitive dissonance effects. For example the Festinger and Carlsmith's experiment where people were paid $1 or $20 to lie. Cognitive dissonance says that people felt bad about lying for $1 because they could not justify the act. With self-perception you conclude that those who were paid $1 must have really enjoyed it because $1 does not justify the act while those who were paid $20 were just doing it for the money. Self-perception theory differs from cognitive dissonance theory in that it does not have a place where people experience dissonance which they seek to relieve. Instead, people simply infer their attitudes from their own behavior in the same way that an outside observer might. Self-perception theory is a special case of attribution theory. Bem ran his own version of Festinger and Carlsmith's famous cognitive dissonance experiment. Subjects listened to a tape of a man enthusiastically describing a tedious peg-turning task. Some subjects were told that the man had been paid $20 for his testimonial and another group was told that he was paid $1. Those in the $1 condition thought that the man must have enjoyed the task more than those in the $20 condition. Bem argued that the subjects did not judge the man's attitude in terms of cognitive dissonance, and that any attitude change the man might have had in that situation was the result of the subject's own self-perception. Whether cognitive dissonance or self-perception is a more useful theory is a topic of considerable controversy there are some circumstances where either theory is preferred, but it is traditional to use the terminology of cognitive dissonance theory by default.
Bem, Daryl J.(1967). Self-Perception: an alternative interpretation of cognitive dissonance phenomena. Psychological Review,74,
Baumeister, Roy F., and Brad J. Bushman. Social Psychology and Human Nature. Belmont: Wadsworth, 2007.
Bem, Daryl J.(1972). Self-Perception Theory. Advances in Experiment Social Psychology,6,