In 1968, a Polish-American social psychologist named Robert Zajonc published a 27-page monograph in the Journal of Personality and Social Psychology titled "Attitudinal Effects of Mere Exposure." The paper documented one of the most robust findings in twentieth-century psychology: humans, given repeated exposure to a neutral stimulus, come to like it more — even when the stimulus carries no information, no semantic content, and no inherent value.
Zajonc's experiments were elegant. He showed subjects unfamiliar Chinese characters, varying the number of times each character appeared. The subjects had no knowledge of Mandarin. The characters were, to them, meaningless squiggles. After exposure, subjects were asked to rate which characters seemed to have more positive meanings.
The characters seen most frequently were rated as having the most positive meanings. Subjects had no idea why. They had no actual information about meaning. The repetition itself had created the preference.
Zajonc called this the Mere Exposure Effect, and over the next five decades it was replicated across hundreds of studies in contexts ranging from face perception, to musical preference, to political voting patterns, to consumer brand choice. The finding is so robust that it's often used as a baseline against which other behavioral effects are measured.
The Mere Exposure Effect is, I'd argue, the most underrated force in modern marketing. Most marketers know about it. Almost none of them use it correctly.
What Subliminal Lipton Proved
The most striking modern replication of Zajonc's finding came from a 2006 paper by Johan Karremans, Wolfgang Stroebe, and Jasper Claus titled "Beyond Vicary's fantasies: The impact of subliminal priming and brand choice," published in the Journal of Experimental Social Psychology. They flashed the brand name Lipton Ice at subjects for 23 milliseconds — well below the threshold of conscious detection. Subjects could not see the words, did not know they had been exposed to them, could not recall them on debrief.
The subjects were then asked to choose between Lipton Ice Tea and a comparable brand they'd been told about beforehand. Among subjects who were thirsty, the subliminal Lipton priming significantly increased Lipton selection. Among subjects who were not thirsty, the effect was much weaker.
This is the important caveat: subliminal exposure doesn't create demand from nothing. It amplifies existing demand. And the effect requires a relevant context. Subliminal Lipton exposure won't make you buy Lipton when you don't want a drink.
But the underlying mechanism — familiarity, even subliminal, biases consumer choice when goal-relevant — was empirically confirmed. The implications for advertising were substantial, although regulatory pressure has since constrained how this can be deployed commercially.
Eurovision and the Power of Repeated Exposure
In 2012, Diarmuid Verrier at Sheffield Hallam University analyzed voting patterns in the Eurovision Song Contest — one of the world's largest live televised music competitions, watched by roughly 600 million people globally. Verrier published his findings in the journal Judgment and Decision Making. He found that contestants who had appeared in semifinals seen by voting audiences did meaningfully better in finals voting than contestants the audience had seen less.
This is the Mere Exposure Effect in commercial form. The audience wasn't voting based on the merits of the song alone. They were partly voting based on which contestant they had seen the most. The mere exposure of the semifinal appearance shifted the preference enough to produce statistically detectable effects in the voting data.
Verrier's study is one of the cleanest large-N demonstrations of the Mere Exposure Effect outside the lab, precisely because the Eurovision dataset offers something most consumer research can't: a near-perfect natural experiment with hundreds of millions of independent voters.
Why This Mechanism Is Different From Forgetting Curve
I've written elsewhere about Hermann Ebbinghaus's 1885 research on the Forgetting Curve, and how Coca-Cola's $4 billion annual advertising budget is essentially a defense against memory decay. That mechanism — repetition prevents loss of memory — is real, but it is distinct from Mere Exposure.
The Forgetting Curve operates on memory retention. The Mere Exposure Effect operates on preference formation. Coca-Cola advertising keeps the brand mentally available. The Mere Exposure Effect keeps the brand positively mentally available. The two compound, but the mechanisms are different.
This distinction matters because the operational implications are different. To defend against the Forgetting Curve, you need spacing. Distributed exposure beats concentrated exposure for memory retention. But for the Mere Exposure Effect, raw frequency of exposure within an evaluation window may matter more than spacing.
The brands that get this right are running both mechanisms simultaneously: spaced exposure for memory durability, plus high-frequency exposure in purchase-decision contexts to bias the choice itself.
The Brand Asset Architecture
Byron Sharp at the Ehrenberg-Bass Institute has argued, in How Brands Grow, that what most marketers think of as "brand differentiation" is largely a Mere Exposure Effect — exposure-driven preference dressed up as quality perception. His argument is that brands grow primarily through mental availability (being recallable in purchase moments) plus physical availability (actually being on the shelf), and that mental availability is built almost entirely by consistent visual and verbal cues repeated across years.
Coca-Cola's famous hourglass bottle (patented 1915, essentially unchanged since), Spencerian-script logo (essentially unchanged since 1887), the polar bear character, the color red — each of these is a Distinctive Brand Asset (Jenni Romaniuk's term in her 2018 book Building Distinctive Brand Assets). Each one accumulates Mere Exposure compound interest over decades.
The brands that consistently win on the Distinctive Brand Asset framework are the brands that refuse to change their visual and verbal identity. Each redesign resets the Mere Exposure clock. Each new logo restarts the preference-formation work from scratch. This is why most challenger brands struggle to gain ground against incumbents — the incumbents have decades of accumulated Mere Exposure equity, and the challenger is trying to catch up on a sub-decade timeline.
What This Means For Smaller Brands
You probably don't have Coca-Cola's marketing budget. The good news is that the Mere Exposure Effect operates on frequency within a defined audience, not on absolute media spend. A small brand with consistent visual and verbal identity, deployed repeatedly within a tightly-targeted customer base, can build Mere Exposure equity inside that segment that rivals what global brands have built across general populations.
The operational instincts that follow:
Pick distinctive assets and never change them. A specific color combination. A particular typographic treatment. A repeated phrase. A consistent visual style. Whatever you pick, commit to it for years, not quarters. The Mere Exposure Effect compounds slowly. Every redesign is a setback.
Increase frequency within your target segment, not breadth across populations. It's better to be the brand your 50,000 ideal customers see weekly than the brand 5 million strangers see once. The Mere Exposure machinery only fires within sustained-exposure contexts.
Use repetition deliberately in single campaigns. The same headline, the same image, the same call-to-action across multiple touchpoints in a campaign window. Marketers chronically over-rotate creative because they get bored of it. Customers are not bored of it. They've barely registered it the first three times.
Audit your distinctive brand assets and protect them. The hourglass bottle, the red soles, the white earbuds — all of these are Mere Exposure investments that took decades to build. A new creative director with a "refresh" agenda can erode that investment in months. The cost is invisible in the short term and devastating in the long term.
What I Take From All This
The thing I find most useful about the Mere Exposure Effect is the humility it requires.
Marketers want to believe that customers choose products because of differentiated quality, value-prop clarity, emotional resonance, or any number of factors the marketer feels they can control through creative work. The Zajonc finding, replicated across sixty years of research, suggests that most of the time, customers are choosing the option they've seen most recently and most often. The differentiation work matters at the margin. The exposure work matters at the foundation.
If you're a smaller brand competing against established incumbents, this is bad news in one direction and good news in another. Bad news: you can't out-spend the incumbents on Mere Exposure within a generalist audience. Good news: you can out-frequency them inside a tight niche, and the compounding will eventually produce category dominance within that niche.
Zajonc's Chinese characters weren't beautiful. They weren't meaningful. They weren't differentiated. They were just seen more. And the brain interpreted seen more as liked more, with no awareness of the substitution.
The implication is that more of what we think of as preference is, in fact, familiarity dressed up as taste. The brands that win the long game are the ones that figured this out and kept showing up — the same logo, the same colors, the same words — for decades, while their competitors kept reinventing themselves into invisibility.
That's the underrated force. It doesn't look like much in any single quarter. It eventually looks like Coca-Cola.