Thomas Aquinas by Carlo Crivelli
Thomas Aquinas by Carlo Crivelli
(Credit Carlo Crivelli — The Yorck Project (2002) 10.000 Meisterwerke der Malerei Public Domain)

The natural laws of human behaviour (not)

Unlike physical objects, which behave according to the laws of gravity or thermodynamics, our behaviour is not that easy to describe

If you have been accessing Wikipedia recently, you may have noticed a fundraising banner popping up. And has been the case for the last few years, the text seeks to encourage visitors to the site to donate using a technique known as social proof. Especially when we are uncertain how to act or behave, and we don’t have a strong preference, we will be inclined to look at what others do or don’t do, so the theory goes.

Taking the lead of our fellow humans

A frequently cited illustration of social proof comes from research by psychologists Noah Goldstein, Robert Cialdini and Vladas Griskevicius. They experimented with different messages intended to encourage hotel guests to reuse their towels, rather than require new ones every morning. Different formulations were tried, like a standard “Save the environment, please reuse your towels during your stay” or more direct “Save the environment, and join your fellow guests in reusing your towels — in a study conducted earlier, 75% of our guests used their towels more than once”. The participation rate for the former message was the lowest at 37.5%, while for the latter it was 44%. A variant personalized to the room ( “guests who stayed in room 313”) achieved nearly 50% participation — a third more than the standard message.

They are getting it wrong! (source: Wikimedia)

Charitable donations look like a prime candidate for the use of social proof. Many of us are a little ambivalent about giving money — yes, we want to be a good person, but no, we don’t want to give away our money just like that, for nothing in return. Being told that many others are donating might just persuade us to do likewise.

And yes, we can see that the Wikipedia campaign message is personalized, just like at the hotel — “To all our readers in <country>” — even the day on which the banner is presented is part of it. But wait: it doesn’t tell us how many people actually donate, but how many people do not give money. This would seem to go squarely against the principle of social proof: if the majority ignores the appeal, and we tend to follow the majority, Wikipedia would encourage us to keep our purse closed.

And every time these Wikipedia banners appear, there are people who feel compelled to demonstrate their superior knowledge, like in this tweet (or this one, or this one), or in this LinkedIn post, or from earlier, this Medium post.

Tweet with author made unreadable, stating “How NOT to use social influence”
Tweet with author made unreadable, stating “How NOT to use social influence”

Are the people at Wikipedia really that stupid that they get something like this so wrong while, strangely, getting so much else right in their campaigns?

Not so stupid

Well, no. As this post explains in detail, the wording in the banners has been fine-tuned to maximize donations through “dozens of A/B tests, with tens of thousands of donors”. (In Wikimedia’s latest fundraising report this question is even explicitly discussed.) The author of the post is Chris Keating, an expert in charitable donating who, for over five years, was a Wikimedia Trustee. He likely knows what he’s talking about, including when he referred to “self-appointed behavioural science experts” pointing out, once again, the error of Wikipedia’s ways earlier this week.

It looks like the critics are committing the informal fallacy of hasty generalization. It is not because social proof sometimes works, to some extent (remember that the most powerful social proof message in the towels experiment left just over half the hotel guests unpersuaded!), that it is like a natural law that applies universally regardless of the context or situation.

In fact, we appear to be capable of remarkable pragmatism when it concerns natural laws. Isaac Newton formulated his law of gravitation in the late 17th century, but for tens of thousands of years before that, our ancestors had been well aware not only of the fact that unsupported objects would invariably fall downwards (and not sideways or upwards), but also that there were exceptions to this (birds and insects which, despite being heavier than air, can overcome the force that operated on falling fruit, stumbling people, and crockery).

Antonov AN-225 aircraft, the largest in the world
Antonov AN-225 aircraft, the largest in the world
640 tonnes, six engines and 32 wheels — still always subject to gravity (photo: Olivier Cabaret CC BY)

Unlike social proof, gravitation does apply to all objects, but as we and our ancestors have been able to observe for as long as we’ve been around, it is not always the only force that applies. We have long been seeing how bats, birds, and bees (and a little less long, aircraft large and small) stay up in the air thanks to lift, how leaves and seeds are picked up by a breeze, and how glowing soot particles soar in the hot air emanating from a fire.

But for some reason, behavioural science seems to produce, in some people, a naïve belief that a single experimental finding at once gives rise to a universal law. This phenomenon appears to afflict novices as well as more experienced people, impairing their ability to think critically and question their hasty conclusions.

A little less hubris

If you see someone who has only just learned about the idea of social proof highlighting the unwanted behaviour as the majority one, it makes sense to suggest they might have misunderstood the principle. But if it concerns Wikipedia, you should really think twice. How likely is it that an organization with their scale and scope would be unaware of the concept of social proof, or — worse still — be aware of it but wilfully choose to ignore it? Maybe they actually know very well what they are doing. Before confidently shooting from the hip, it’s worth doing a bit of research.

For social proof, like most behavioural phenomena, is neither universal, nor the exclusive explanation of human behaviour. When we are not sure what is the right thing to do, we may well take our cues from what others are doing. But sometimes we do want to identify with a small minority. Would a member of the “1%” really aspire to become one of the “99%”, or instead seek to join the “0.1%”?

Human behaviour is the aggregation of numerous stimuli and tendencies, some of which may even directly contradict each other. Are our choices when we buy a new car, or a washing up liquid led by our preference to stick with the familiar (status quo bias), or by the desire for something new (novelty bias)? Will we change someone’s mind if we repeatedly point out their delusions (illusory truth effect) or will they instead dig their heels in ever deeper (backfire effect)? Will we use our life savings to start up a business around our brilliant idea (optimism bias) or stick with our humdrum 9–5 job (risk aversion)?

It all depends. Our behaviour cannot easily be captured in a few simple tendencies. It is, perhaps more than any domain of study, an illustration of what Aristotle is claimed to have said: “The more you know, the more you know you don’t know”. A little less hubris would suit us well.

(The banner illustration depicts Thomas Aquinas, who revived and developed the concept of natural law from ancient Greek philosophy.)

Originally published at on July 17, 2020.

Thanks for reading this article — I hope you enjoyed it. Please do share it far and wide — there are handy Twitter and Facebook buttons nearby, and you can click here to share it via LinkedIn, or simply copy and paste this link. See all my other articles featuring observations of human behaviour (I publish one every Friday) here. Thank you!

Written by

Accidental behavioural economist in search of wisdom. Uses insights from (behavioural) economics in organization development. On Twitter as @koenfucius

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