Why we like what we have seen most often: the mere-exposure effect

A song you did not like the first time starts to grow on you after a few weeks on the radio. A face you see every day on the bus seems closer. A brand you see everywhere seems more trustworthy. Behind these experiences lies a phenomenon psychologists call the mere-exposure effect.

Zajonc's experiments

In 1968 the Polish-born American psychologist Robert Zajonc showed participants unfamiliar words, Chinese characters and photographs of faces, some more times than others. Then he asked them to rate how much they liked them. The more times they had seen a stimulus, the more positively they rated it, even when it meant nothing to them.

Later studies showed that the effect works even when stimuli are shown so briefly that people do not realise they have seen them. A 1989 meta-analysis by Robert Bornstein combined over 200 experiments and confirmed the effect, noting that it is stronger with brief exposures and fades after many repetitions.

Why it happens

A widespread explanation is that familiar things are processed more easily by the mind, and this ease is experienced as pleasant. Another explanation concerns safety: what we have seen many times without anything bad happening seems safer.

What seems "good" to us is sometimes simply what has become familiar.

Where we meet it

• In advertising: repeating a brand, even without arguments, increases liking for it.
• In politics: names we see more often on posters and screens seem more familiar and sometimes more trustworthy.
• In relationships: people we meet often, such as neighbours or colleagues, tend to become closer to us.
• In the news: a claim we hear often seems more true, even when it is not.

How to choose more consciously

1. Ask: do I like this because it is good, or because I have seen it often?
2. Look for evidence before believing a claim you have heard many times.
3. Give a chance to what is new. A book, music or a person you do not like at once may grow on you after a few encounters.
4. Use it to your advantage: if you want to like something healthy, such as vegetables or walking, make it a regular part of the day.