Richard Shotton
Aug 9, 2018

The pratfall effect

Book excerpt: How flaws make a brand more appealing.

The pratfall effect
The following is a chapter from Richard Shotton's The Choice Factory, a book about applying behavioural science and psychology to advertising. 

Your main task this afternoon is to interview the last two candidates for the position of manager on your team. At the close of the second interview you realise both candidates have the same relevant experience, strong academic results and practical ideas to implement once they start. You’re wondering how you’ll ever choose between them. As the final candidate gets up to leave, he catches his foot awkwardly on the table leg, upending the dregs of his coffee over the new floor. He leaves ashen-faced.

Who do you think you’ll end up picking? If the pratfall effect is correct, it’ll be the clumsy candidate.

The bias was discovered in 1966 by Harvard University psychologist Elliot Aronson. Along with his colleagues, Ben Willerman and Joanne Floyd, he recorded an actor answering a series of quiz questions. In one strand of the experiment, the actor – armed with the right responses – answers 92% of the questions correctly. After the quiz, the actor then pretends to spill a cup of coffee over himself (a small blunder, or pratfall).

The recording was played to a large sample of students, who were then asked how likeable the contestant was. However, Aronson split the students into cells and played them different versions: one with the spillage included and one without. The students found the clumsy contestant more likeable. In Aronson’s words:

The pratfall made the contestant more appealing as it increases his approachability and makes him seem less austere, more human.

Does the bias work on products sixty years later?

It’s not just clumsiness that increases appeal. Jenny Riddell and I investigated whether product flaws could boost appeal. We replicated an unpublished study by Australian consumer psychologist Adam Ferrier by asking 626 nationally representative people which of two cookies they preferred. The biscuits were identical apart from one small difference: one had a rough edge; the other a perfectly smooth one.

The cookie with the rough edge was the overwhelming favourite: 66% preferred it. The small imperfection didn’t detract from its appeal, but boosted it.

How to apply this effect

1. Flaunt your flaws

The best application is to admit that your brand has a flaw.


Not if you consider how many of the leading ad campaigns have done so.

One of the earliest examples was the long-running American VW ad campaign by DDB, which from 1959, gloried in the

flaws of the Beetle. The looks of the car were gently mocked with one print ad featuring a photo of the lunar module and the headline, “It’s ugly but it gets you there”. Another referenced the size of the car with the line “Think Small”. And my favourite drew attention to the slow speed in the body copy: “A VW won’t go over 72 mph. (Even though the speedometer shows a wildly optimistic top speed of 90.)”

The trade magazine Ad Age ranked it the best ad of the 20th century.

Bernbach’s agency repeated the approach with Avis. The tagline emphasised the car rental’s relative unpopularity compared to Hertz: “When you’re only number two you try harder. Or else.” Within a year of the campaign launching, Avis made a profit of $1.2m – the first time they had broken even in a decade. The approach was so successful it ran for more than 50 years.

Then there’s Lowe’s campaign for Stella Artois, “Reassuringly Expensive” and Guinness’s “Good things come to those who wait”.

Admitting weakness is a tangible demonstration of honesty and, therefore, makes other claims more believable. Further to that, the best straplines harness the trade-off effect. We know from bitter experience that we don’t get anything for free in life. By admitting a weakness, a brand credibly establishes a related positive attribute.

Guinness may take longer to pour but boy, it’s worth it. Avis might not have the most sales but it’s desperate to keep you happy.

Everyone assumes that brands are fallible, so if a brand is open about its failings, it can persuade consumers that its weaknesses lie in inconsequential areas. This theory partly explains the success of budget airlines. At launch they openly admitted that the trade-off for cheap prices was compromised service: no seat reservations and a pitiful luggage allowance. If they hadn’t admitted as much, consumers may have assumed the cost-cutting had come at the expense of safety.

2. Make sure this tactic suits your brand

A twist in Aronson’s experiment suggests caution. He repeated the set-up but this time the actor feigned incompetence and answered only 30% of the questions correctly. Once again students rated his appeal. In this scenario the clumsy spillage made him less appealing. The pratfall effect has a multiplicative effect rather than a purely positive one. It makes strong brands stronger, but weak brands weaker.

3. More than just ads

Finally, it’s not just a matter of tweaking the copy in your ads. It should affect how you deal with unflattering customer reviews. Many brands hide the negative reviews. However, a 2015 study, by Northwestern University’s Spiegel Research Centre, analysed 111,460 product reviews across 22 categories and linked ratings to probability of purchasing. It found that likelihood of purchase didn’t peak with perfect scores but at 4.2-4.5 out of 5.

Perfect ratings had less impact because they were seen as too good to be true. According to the authors:

Counter-intuitive as it may seem, but negative reviews may have a positive impact because they help establish trust and authenticity. Consumers understand that a product can’t be all things to all people.

My favourite such example comes from Iain Banks’s 1984 debut novel, The Wasp Factory. Banks was thirty when he finally persuaded a publisher to release one of his works. The delay was not for want of trying. Over the previous 14 years he had written four novels, all of which had been rejected by publishers.

Despite struggling for so long to gain recognition, Banks broke with tradition and insisted that the novel included both positive and negative reviews within the blurb. Some of the reviews were caustic, such as the following from the Sunday Express:

A silly, gloatingly sadistic and grisly yarn of a family of Scots lunatics, one of whom tortures small creatures – a bit better written than most horror hokum but really just the literary equivalent of a video nasty.

The Times was even more damning:

As a piece of writing, The Wasp Factory soars to the level of mediocrity. Maybe the crassly explicit language, the obscenity of the plot were thought to strike an agreeably avant-garde note. Perhaps it’s all a joke meant to fool literary London into respect for rubbish.

Banks’s chutzpah paid off. His distinctive approach got him noticed and the sheer outrage of many critics meant its positioning as a powerfully moving book had credibility. The publicity helped create a bestseller, while positioning him as an independent thinker.

If it’s a successful approach, why is it rare?

I have listed half a dozen examples of the pratfall effect and there are a handful of others. But they stretch over a period of nearly 60 years, making them a minuscule proportion of the tens of thousands of ads that have run over that time.


The rarity is explained by the principal-agent problem, a theory first suggested by Stephen Ross, Professor of Finance at the MIT Sloan School of Management. He suggested that there is a divergence between the interest of the principal in a company, the shareholders, and the agent, the staff.

What is in the interest of the brand, the principal, is not in the interest of the marketing manager, the agent. If the campaign flops it might be the end of the brand manager’s career. Imagine explaining to your CEO as sales dive that the key message of your campaign was that the brand was expensive. Even referencing Aronson’s research won’t save you.

For those prepared to embrace a modicum of career risk then the best chance of growing your brand is to flaunt your flaws. The principal-agent problem ensures it will always be a distinctive approach. For those interested in safe career progression then you may want to consider another route, such as avoiding the winner’s curse. Luckily for you that’s what the next chapter is about.

Richard Shotton is deputy head of evidence at Manning Gottlieb OMD in London. The above is a chapter from his book, The Choice Factory: 25 behavioural biases that influence what we buy, which is available through Amazon, through Kinokuniya in JapanSingaporeMalaysiaTaiwan and Thailand, and in book shops.

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