The Mere-Exposure Effect

Why do people often come to like a song after hearing it a few times, even if they did not care for it at first? One explanation is the mere-exposure effect: the tendency to develop a preference for things simply because they are familiar. The effect was described in detail in 1968 by the psychologist Robert Zajonc, who showed people unfamiliar words, Chinese characters, and photographs of faces. [A] The more often participants had seen an item, the more positively they rated it. [B]

[C] Later studies found that the effect occurs even when people are not aware of having seen something before. In some experiments, images were flashed on a screen so briefly that participants could not report what they had seen, yet they still preferred those images to new ones. [D] This suggests that familiarity does not need to be conscious to influence our feelings.

Researchers have suggested that the effect makes sense from an evolutionary point of view. Something that we have encountered many times without being harmed is probably safe, whereas something new could be dangerous. The effect has limits, however. If people dislike something strongly at the start, repeated exposure may make them dislike it even more, and too much repetition can lead to boredom. This is one reason advertisers often change their commercials rather than show exactly the same one again and again.