Mere exposure effect

The mere exposure effect is the tendency to like things more simply because we have seen them before. No reward, argument or explanation is needed. A song you thought was grating becomes catchy after a week on the radio; a pair of shoes that looked strange in March looks right by May. Familiarity on its own nudges our opinions in a friendly direction, and modern advertising is built to supply it.

A student in a black bag

The social psychologist Robert Zajonc opened his 1968 monograph on the subject with a news story. In February 1967, the Associated Press reported that a student at Oregon State University had been attending a speech class for two months inside a large black bag, with only his bare feet showing. The professor knew who was inside; the 20 other students did not. The professor said the class had gone from hostile to curious and, in the end, to friendly toward the black bag. Nothing about the bag had changed except that the students kept seeing it.

Zajonc then tested the idea directly. In one experiment, 72 people were shown twelve seven-letter nonsense words made to look like Turkish. Each word was shown on a card for about two seconds, and the participant said it aloud. Some words were shown once, some twice, some five, ten or twenty-five times, and some not at all. Afterward, the participants were told the words were Turkish adjectives and asked to guess, on a seven-point scale, whether each one meant something good or bad. The more often a word had been seen, the more likely people were to guess that it meant something good.

To rule out the effect of saying the words aloud, Zajonc repeated the experiment with Chinese-like characters that participants only looked at, and got the same pattern. Then he used faces. Students were shown photographs of graduating seniors from the Michigan State University yearbook, each a different number of times, and asked how much they thought they would like each man. Liking rose with the number of exposures for most of the faces.

In 1980 William Kunst-Wilson and Zajonc took the idea further. They showed people shapes so briefly that afterward they could not reliably say which ones they had seen. Asked which shapes they liked, people still tended to prefer the ones they had been shown. Familiarity had shaped their taste without their noticing.

Why familiarity feels like liking

One common explanation is that familiar things are easier to process. We recognize them faster and make sense of them with less effort, and that ease feels pleasant, so we read it as liking. Another is that familiarity signals safety: something we have met many times without harm seems less likely to be a threat. Either way, most of the research involves things that start out neutral or new, which describes most products before you have bought them.

How repetition builds a chain

Picture a style of chunky loafer that begins turning up in your feed, in ads and on people you follow. At first they look odd. After three weeks of seeing them every day, they look right, and you buy a pair for $160. But the loafers are always shown with cropped wide trousers, so the trousers start to look right too, and $95 later you own a pair. The ads, meanwhile, have moved on to the bag that appears in the same photos. Each item became familiar before you decided you wanted it, and each one came already styled beside the next.

How sellers buy familiarity

• Frequency. Advertising plans count how many times a person sees a message, because repetition builds familiarity.
• Retargeting. Ads that follow you from site to site after you look at a product keep it in front of you until it feels like yours.
• Email cadence. Regular messages keep a brand and its products in view, even when you delete them unread.
• Styling and placement. The same products appear again and again in photos, videos and the feeds of people you follow, always shown with the items that go with them.
• Consistency. Logos, colors and packaging stay the same so that every exposure adds to the last.

How to see less of what you do not need

1. Cut the supply. Unsubscribe from store emails, unfollow shopping accounts and turn off ad personalization where the setting exists. Less exposure means less unearned liking.
2. Check your old list. Before buying something you keep seeing, ask whether it was on any list of yours before it started following you around. If not, the repetition may be doing the wanting.
3. Wait with the feed off. Put the item on a list and spend some time away from the ads that keep showing it. The 30-day rule works better when the item is not in front of you every day.
4. Browse with a purpose. Scrolling shops for entertainment is exposure you are choosing. Shop when you have a list, and close the tab when the list is done.

Where it meets the Diderot effect

The Diderot effect starts when something new makes what you own look wrong. Mere exposure can start it without a purchase at all. Weeks of seeing the same styled rooms, outfits and kits teach your eye a new standard, and your own home and wardrobe begin to look dated by comparison. By the time you buy the first piece, the chain has been rehearsed in your feed. A wardrobe built around a personal uniform gives your eye a standard of your own to come back to, and the bandwagon effect explains why the things you see most are so often the things everyone is buying.