Daryl Bem

Who they are

According to his curriculum vitae, Bem read physics at Reed College, did graduate work in physics at MIT, and took a PhD in social psychology at the University of Michigan in 1964. He taught at Carnegie Mellon University from 1964 to 1971, at Stanford University from 1971 to 1978, and has been at Cornell University since 1978, where he is a professor emeritus. He was a visiting professor at Harvard in 1987 and 1988.

His best-known contribution to this site's subjects is self-perception theory. It began as an alternative to cognitive dissonance theory, which explained attitude change by the discomfort of holding inconsistent beliefs. Bem argued that no such discomfort was needed. A person asked what they think can answer the way an outside observer would: by looking at what they did.

Key papers

Bem, D. J. (1967). Self-perception: An alternative interpretation of cognitive dissonance phenomena. Psychological Review, 74(3), 183-200. The paper that set out the alternative to dissonance theory.

Bem, D. J. (1972). Self-perception theory. In L. Berkowitz (Ed.), Advances in Experimental Social Psychology, Vol. 6, pp. 1-62. Academic Press. The long statement of the theory, and the one a citation should point to. It develops the claim that people infer their attitudes from their behaviour, most readily when internal cues are weak or ambiguous.

Key ideas

The core claim is that self-knowledge is partly inference. A person watches what they do, notes the setting, and concludes what they must believe or prefer. The more clearly an inner state is felt, the less the inference is needed. The more ambiguous it is, the more behaviour fills the gap.

The idea was applied to the foot-in-the-door effect, where agreeing to a small request makes a larger one easier to grant. A 1975 field experiment tested the self-perception explanation directly. Later reviews were critical: a 1983 meta-analysis judged the explanation too imprecise to make clear predictions, and a 1984 meta-analysis called it seriously flawed as an account of that effect. The theory is therefore best held as a description of a plausible mechanism, not as a proven explanation of every compliance result.

Behavioural economics later turned the inference into a choice. In the self-signalling model of Prelec and Bodner, a person selects an action partly for the reading it will give them. Bem's version needs no such motive, and in its own formulation it does not require an audience.

Where this site uses him, the rule is the one it applies to every originator: credit the paper, state the mechanism, and keep the claim no larger than the tests behind it.

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