The Discovery of the Effect and the Experimental Evidence
The mere exposure effect is a psychological phenomenon systematically demonstrated by Robert Zajonc in a landmark 1968 paper. It refers to the finding that repeated contact with a stimulus, on its own and without acquiring any information whatsoever about that stimulus, raises liking for it and the sense of familiarity attached to it. In Zajonc's experiments, participants were shown meaningless Chinese-style characters, photographs of unfamiliar faces, and nonsense syllables at differing frequencies, after which their liking for each item was measured. The items presented more often were rated more favourably. The effect does not require conscious cognition and has been confirmed to occur even under subliminal presentation, where the exposure is too brief to be consciously perceived. Its magnitude is moderate, with a meta-analysis by Bornstein (1989) covering 208 experiments returning r = .26, but it is remarkably robust and has been replicated across a wide range of sensory modalities including vision, hearing and taste.
Mere Exposure and Interpersonal Attraction
The mere exposure effect matters considerably in the formation of interpersonal attraction. Liking develops towards people we encounter frequently in daily life, whether at the same workplace, in the same class or on the same commuter train, even in the absence of any particular interaction with them. In an experiment by Moreland and Beach (1992), confederates attended a university course at differing frequencies while having no contact at all with the other students, and ratings of liking for those confederates rose with attendance frequency. Several mechanisms have been proposed to explain this. One is processing fluency: a familiar stimulus is easier to process, and that ease is misattributed as liking. A second is uncertainty reduction, in that repeated contact confirms the stimulus poses no threat and a sense of safety follows. A third is classical conditioning, whereby if contact occurs in a neutral or pleasant context, the pleasantness of that context becomes conditioned to the stimulus itself.
Limits of the Effect, and What an Opportunity to Meet Is Worth
The mere exposure effect has several important limits. First, where the initial impression is negative, repeated contact may not increase liking at all but instead intensify dislike. Second, the effect saturates once exposure passes a certain point, beyond which no further gain in liking is observed. Third, the liking generated by mere exposure is comparatively shallow, and it guarantees neither deep intimacy nor long-term relationship satisfaction. The effect also shows how much weight the sheer opportunity to meet carries in the first place: however well matched two people may be in personality, a relationship cannot begin without occasions for contact. It is also necessary to distinguish liking produced by mere exposure from substantive compatibility of personality. Liking someone because you see them often and liking someone because your personalities fit are different mechanisms, and the former on its own cannot predict the quality of a relationship over the long term.