Robert Zajonc

Who they are

Zajonc is best known on this site for the mere exposure effect. The monograph begins by reprinting a 1967 Associated Press story about a student at Oregon State University who attended a class inside a black bag, and whose classmates, according to the professor, moved from hostility to curiosity and finally to friendship.

This page records only what the papers and their published records state. Biography beyond the cited work is not given here.

Key papers

Attitudinal effects of mere exposure (1968). The monograph combined correlational evidence with experiments. On the correlational side, it noted that words standing for good, desirable and preferred things are used more often than words for bad ones. The experiments then tested whether frequency could produce liking.

In the first experiment, 72 people were told they were learning Turkish adjectives. They saw and pronounced twelve seven-letter nonsense words, each shown 0, 1, 2, 5, 10 or 25 times, and rated each on a scale from bad to good. Words seen more often were rated more favourably. A second experiment used Chinese-like characters viewed for about two seconds each, with the same pattern. A third used photographs of graduating seniors from Michigan State University; nine of the twelve faces were liked more the more often they had been shown. A fourth found that skin conductance responses to nonsense words fell as the words became familiar.

Key ideas

The central idea is that exposure alone, with nothing attached to it, can make something more likeable. The exposures in the 1968 experiments were brief but clearly visible. Later work tested exposures too brief to be recognised, which is a separate question.

The idea has been tested many times since. Robert Bornstein's 1989 meta-analysis reviewed the two decades of research that followed the monograph, and a 2017 meta-analysis by R. Matthew Montoya and colleagues found that liking rises and then falls with repetition for visual stimuli.

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