In 1968, a graduate student at Oregon State University showed up to a psychology class wearing a large black bag, feet visible, and sat in the back of the room all term. The class began hostile — a bag doesn’t belong in a lecture hall — then wary, then curious, and by the end of the semester the students were genuinely friendly toward it. The professor, Charles Goetzinger, was testing an idea from Robert Zajonc: that simply being exposed to a thing over and over is enough to make you like it. Zajonc had spent the 1960s demonstrating this with words, pictures, faces, and sounds. The bag was the strangest proof he ever got.
🧠 The Bag in the Back of the Room
Zajonc noticed something about how every organism meets novelty: a new stimulus first triggers fear and avoidance, each repetition drains a little of that fear, and eventually the once-scary thing becomes interesting, then pleasant. He showed it with nonsense words and Chinese characters flashed briefly to participants who couldn’t read them — the ones they had seen before were rated as more positive. He even played tones to chicken eggs before they hatched, and the chicks, once out, consistently chose the tone they had heard in the shell. Liking, he concluded, does not require understanding. You can grow fond of something you have no idea what it is.
🤔 The Shape You Never Saw
The strangest demonstration came in 1980, when Zajonc and William Kunst-Wilson flashed irregular polygons at participants for a single millisecond — far below what anyone could consciously register. Asked whether they recognized any of the shapes, people were guessing at chance level. Asked which shapes they preferred, they reliably picked the ones they had supposedly never seen. Zajonc’s slogan became “preferences need no inferences”: affect arrives before cognition, and your feelings run on a faster circuit than your thoughts. A 1989 meta-analysis of 208 experiments found the effect solid (r = .26) — and oddly, the liking boost is actually stronger for subliminal exposure than for conscious exposure. The less aware you are, the harder it works. It also has limits: liking peaks after ten to twenty exposures and can slide into boredom (the inverted-U), and for people you already dislike, more exposure makes things worse, not better.
🔗 The Quiet Engine of Ads and Bonds
Advertising runs on this whether or not anyone remembers the ad. In one study, students reading an article with banner ads at the top rated the repeatedly shown banner more favorably than ones they saw less often — exposure alone left a trace. That’s why new brands blast frequency: unfamiliar things benefit most from repetition. Established brands, by contrast, can oversaturate and slide into ambivalence, which is one reason your brain eventually learns to stop seeing banners at all. For a companion product, “it grew on me” isn’t a metaphor — it’s the mechanism. Every time a user comes back, they’re stacking exposures, and familiarity quietly becomes trust, which becomes the feeling that this was somehow meant to be. For writers, it’s the same quiet engine: characters and places earn affection by reappearing until the reader would miss them.
🎲 The Mirror Test
Here’s a two-minute experiment. Take a photo of your face and flip it horizontally in any photo app. To you, the flipped version will look “more right” — it’s the face you see in the mirror every day. Show both versions to a friend, and they’ll pick the original, because that’s the face they actually see. In 1977, Theodore Mita and colleagues ran exactly this test and both preferences showed up cleanly. You have two faces, and neither is the one you think. Bonus: the chicks. The egg-hearing experiment means your taste in sounds can be shaped before you’re born — so the lullaby that calms you might just be the one you heard first, not the one you loved most.