Why a Minor Flaw Makes Brands Likeable

Why We Look · 11 October 2026

A minor flaw can make a brand more likeable, but only when it is small, comes after the good news, meets a reader who is not looking closely and comes from a brand already seen as competent.

Key takeaways

In Elliot Aronson's 1966 study of 48 students, the boost for a brilliant contestant who spilled coffee was not statistically reliable on its own; the clearer result was that a blunder hurt an average one.
In 2012 studies by Danit Ein-Gar and colleagues, a mild negative raised purchase intentions for people reading with little effort, and lowered them for careful readers.
Order mattered: a small flaw helped after the positives, not before.
The conditions: keep it small, put it last, expect skimmers, and be competent first.

A minor flaw can make a brand more likeable, but only under narrow conditions, and the most famous experiment behind the idea shows less than it is usually said to. The story starts with a spilled cup of coffee.

Advertisers have long believed in the power of admitting a weakness. Volkswagen sold a small car by calling it small. Avis sold car hire by admitting it was number two. Richard Shotton's The Choice Factory, a guide to behavioural biases for marketers, gathers these campaigns under the heading of the pratfall effect, at pages 123 to 129, and advises brands to flaunt their flaws. The advice holds, but only under conditions the slogan leaves out.

Read the 1966 study before you quote it

The pratfall effect comes from an experiment by Elliot Aronson, Ben Willerman and Joanne Floyd, published in Psychonomic Science in 1966. Forty-eight male students at the University of Minnesota listened to a tape of a supposed applicant for a college quiz team answering 50 hard questions. In one version he was brilliant, answering 92 per cent correctly and mentioning that he was an honours student and yearbook editor. In the other he was average, answering 30 per cent correctly.

Half of the tapes ended with a small disaster. The contestant spilled coffee over his new suit. Listeners then rated how much they liked him.

The result that made the study famous was the brilliant contestant who spilled his coffee. His average likeability score was 30.2, against 20.8 for the brilliant contestant who did not. A minor flaw seemed to make a capable person warmer.

The paper's own statistics tell a more careful story. The rise for the brilliant contestant was not statistically reliable on its own. What was reliable was the other half: the average contestant who spilled his coffee was liked much less, with a score of minus 2.5 against 17.8 without the accident. The clearest finding of the original study is that a blunder hurts an ordinary performer, not that it helps an excellent one.

The sample was also small, 48 people, all young men, and we found no direct replication of it. It may well be right about the brilliant contestant. It simply does not show it as firmly as it is usually reported.

That matters for brands, because most brands are not the brilliant contestant. If the original evidence points anywhere with confidence, it is that a visible mistake from an unremarkable performer makes things worse.

Look for the blemish that follows praise

A better test of the idea for products came in 2012. Danit Ein-Gar, Baba Shiv and Zakary Tormala, in the Journal of Consumer Research, called it the blemishing effect: a small dose of negative information can make people more positive about a product, but only in particular conditions.

In one study, 141 people read a description of hiking boots. For some, the list of positive features ended with a mild negative, that the boots came in only two colours. When people were reading with little effort, the blemished description raised purchase intentions, from 3.29 to 4.26 on a seven-point scale. When people were reading carefully, it did the opposite, lowering them from 4.24 to 3.36.

A minor flaw helps when people are not examining the message closely, and it hurts when they are.

A field study made the same point with chocolate. Students were offered a chocolate bar described, in one version, as a bit broken. Students approached just before an exam, when their attention was elsewhere, bought more of the blemished bar than the unblemished one. Students who were not distracted bought fewer.

Order mattered too. In a further study, a minor flaw helped when it came after the positives, and not when it came first: under low effort, on that study's measure, the positive-then-negative description scored 2.17 against 1.45 for the same information in the reverse order. Under high effort, order made no difference. The authors' explanation is that a minor flaw, arriving after the good news, makes the good news seem more credible to someone who is not scrutinising it.

Ask whether your customer is paying attention

The blemishing studies give the pratfall effect a boundary that the advertising folklore lacks. A minor flaw helps when people are not examining the message closely, and it hurts when they are.

That may help explain the classic campaigns. A slogan about being number two can be taken in at a glance, by people who are not weighing specifications. In that setting, an admitted weakness can make the rest of the message more believable. A buyer comparing two products side by side, reading every line of the description, is in the high-effort condition, where the same flaw reads simply as a flaw.

It also explains why the effect is rarer in practice than the advice to flaunt your flaws suggests. Shotton offers an economic reason: the person who signs off an advert risks blame if the admitted flaw backfires, so few take the risk. The research suggests a second reason. Many of the places where a brand could admit a weakness, such as product pages, reviews and comparison sites, are exactly the places where customers pay close attention.

For readers deciding whether to trust a brand that admits a weakness, the evidence suggests asking a simple question. Is the admitted flaw minor and beside the point, placed after a run of strong claims? If so, it may be there partly to make those claims more believable. That is not dishonest, but it is a technique, and it works best on someone who is not looking closely.

Reviews are where many shoppers now meet a small flaw. Shotton recommends that brands show their negative reviews, and the blemishing research gives a reason that goes beyond honesty. A page of uniformly glowing reviews invites suspicion, while a few mild complaints among many positive ones can make the praise more believable. The same research adds the condition: the complaints have to be minor, and the shopper has to be reading quickly enough to take the overall impression rather than weighing every line. A minor flaw in a review section helps. A pattern of serious complaints does not become charming because it is displayed openly.

For shoppers, the useful habit is to read what the complaints actually say, not only how many there are.

Stop hiding a small flaw, but only a small one

The practical rules that follow are narrow, and they are ours, drawn from the studies rather than tested as a package.

A minor flaw has to be genuinely small and beside the point: two colours on offer, or a chocolate bar that is a bit broken, rather than anything that touches whether the product works. It should come after the positives, not before. It works on readers who are skimming, not on those comparing closely. And it is safest for a brand already seen as competent; the 1966 study's clearest result is that for an ordinary performer, a visible mistake hurts.

Put as a checklist, the conditions are short:

Keep it small. A minor flaw, beside the point of the purchase.
Put it last. After the positives, not before.
Expect skimmers. It helps quick readers and can hurt careful ones.
Be competent first. The clearest 1966 result is that a blunder hurts an ordinary performer.

None of the studies tested large flaws, repeated flaws, or flaws in safety or reliability, and nobody should read the pratfall effect as a reason to admit those cheerfully. A minor flaw can humanise. A serious one is just a problem.

The 1966 coffee cup has done a great deal of work in marketing. The most reliable thing it showed is that a stumble hurts an ordinary performer. Brands that want to borrow the idea should first ask which of the two their customers think they are. The answer decides whether a stumble helps.

Common questions

What is the pratfall effect?

The idea, from a 1966 study by Elliot Aronson and colleagues, that a competent person becomes more likeable after a small blunder. In that study the boost for the competent contestant was not statistically reliable on its own; the clearer result was that an average contestant who blundered was liked less.

Does admitting a small flaw help a product?

Sometimes. In 2012 studies by Danit Ein-Gar and colleagues, a minor negative raised purchase intentions when people read with little effort and the negative came after positives. When people read carefully, it lowered them.

Should brands advertise their weaknesses?

Only small ones, after the positives, in settings where people are not scrutinising closely. The evidence does not support admitting serious flaws, and a blunder appears to hurt a brand already seen as ordinary.

Sources

Aronson, E., Willerman, B., & Floyd, J. (1966). 'The effect of a pratfall on increasing interpersonal attractiveness.' Psychonomic Science, 4(6), 227-228. doi:10.3758/BF03342263. Full text read: 48 male students; superior with pratfall 30.2, without 20.8; average without 17.8, with pratfall -2.5; the rise for the superior contestant was not significant on its own.

Ein-Gar, D., Shiv, B., & Tormala, Z. L. (2012). 'When blemishing leads to blossoming: the positive effect of negative information.' Journal of Consumer Research, 38(5), 846-859. doi:10.1086/660807. Four studies; study 1, 141 participants; study 2, a field study with chocolate.

Shotton, R. (2018). The Choice Factory: 25 Behavioural Biases That Influence What We Buy. Harriman House. Read in full by this publication, with a reliability audit. Bias 18, pp. 123-129.

A note on scope: no direct replication of the 1966 study was located. The four-point checklist is this publication's synthesis, not a tested package.