The pratfall effect
Researchers have tested this many times, in different places, over many years, and they keep finding the same result. This one is safe to trust.
People listened to a recording of someone doing well on a quiz, sounding intelligent and competent. In one version, at the end, the person clumsily spilled a cup of coffee on themselves. In the other version, no spill. Then listeners rated how likeable the person was. The clumsy, coffee-spilling version was rated more likeable, not less. The blunder made the competent person more appealing, not weaker. Researchers named it the pratfall effect. But there was an important condition. The effect only worked for people who had already come across as highly competent. When someone who seemed average or mediocre spilled the coffee, it just made them look worse. A visible flaw makes an impressive person more human and more likeable, but it does nothing for someone who has not first established they are good.
A small visible flaw makes a genuinely capable person more likeable, not less, because it signals they are real rather than performing. This cuts against the instinct to appear flawless, in yourself and in what you look for in others. Someone who presents as perfectly polished, with no rough edges and no admitted weaknesses, often reads as rehearsed or guarded, and real expertise usually comes with some visible imperfections. A candidate who can name a genuine weakness, or who is a little awkward while clearly skilled, is usually showing you something more trustworthy than someone whose surface is seamless.
Charisma says a dozen learnable tactics get someone rated as more charismatic and more leader-like, so the impression of a natural leader can be trained. The pratfall effect says a competent person who spills coffee on themselves is rated more likeable, not less, because the flaw reads as real. Polish wins in one and a flaw wins in the other, and both are measuring the same thing: your reaction, not their ability. The pratfall only helps someone already seen as competent, and charisma can be trained to produce that impression. Neither tells you what the person can do. Score the work on its own, and treat both the shine and the endearing stumble as facts about you.
Source: Aronson, Willerman and Floyd, The effect of a pratfall on increasing interpersonal attractiveness, Psychonomic Science, 1966: 48 students, and the pratfall raised liking only for the highly competent candidate.
Robert Cialdini, 1984
The book that came out of Cialdini's three years working undercover in sales, fundraising and advertising. Read it once to understand persuasion and once to notice it being used on you.
The Saturday letters
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