杏吧原创

Knowing you’re being manipulated doesn’t stop it from happening

Brain Scanner is Simon Oxenham's monthly column that sifts the pseudoscience from the neuroscience

Donation box labelled "Donate" in red letters
Do subtle attempts to change your actions still work when you know they鈥檙e happening? It was thought that it鈥檚 easier to manipulate people who are kept in the dark, but it now seems we don鈥檛 mind being clearly 鈥nudged鈥 to behave in certain ways.

A nudge uses an understanding of human behaviour to encourage people to do particular things. Nudges work without imposing rules or big penalties 鈥 they are more subtle approaches for promoting certain actions.

The term was coined in 2008 by Richard Thaler at the University of Chicago and Cass Sunstein at Harvard University. Since then, politicians around the world have become enchanted by the idea, with the UK government even establishing a 鈥渘udge unit鈥. Formally known as the Behavioural Insights Team, it has used large randomised controlled trials to formulate advice on everything from to .

In one study, the team found that rephrasing the message on the UK government鈥檚 organ donor website . The original message politely asked people to join the register, but changing it to 鈥淚f you needed an organ transplant, would you have one?鈥 helped boost the sign-up rate by the equivalent of 96,000 extra registrations a year.

But is it ethical to alter people鈥檚 behaviour in this way without their knowledge? The UK鈥檚 nudge unit has for moving to private ownership 鈥 a move which means it is no longer subject to freedom of information requests.

Perhaps this ethical quandary can be avoided, because an explicit nudge can work, too 鈥 a finding that counters the ideas of philosopher Luc Bovens at the London School of Economics, who had suggested that nudges work best . Now Hendrik Bruns at the University of Hamburg, Germany, and his team .

Donation game

The team gave student volunteers 鈧10 each and asked them how much, if any, they would like to donate to a fund to protect against climate change. Any money they didn鈥檛 donate would be theirs to keep.

Some of the volunteers were told no extra information, while others were told that the default donation was 鈧8, a move inspired by studies that have found that default options influence economic decision-making. But some of these volunteers were also told that the preselected default might have been chosen to influence their behaviour 鈥 whereas others were told that it was definitely picked for this purpose. A fifth group was told that the default may have the power to influence their decision, and that it had been purposely picked to increase the amount they gave.

It turned out that the average donation for those who were nudged was 鈧2.87, compared with only 鈧1.67 for those who weren鈥檛 told of any default. None of the suggestions that the default may change behaviour had a significant effect on the power of the nudge. People who weren鈥檛 in the dark still donated more money.

Their findings are supported by . In one study, researchers found they could nudge people into choosing healthier snacks next to the cash register in shops 鈥 and that by an accompanying sign reading 鈥渨e help you make healthier choices鈥.

This line of research echoes growing evidence that placebos work even if we know they are fakes. This was first demonstrated in people seeking treatment for irritable bowel syndrome, and has recently turned up again in a .

The fascinating lesson seems to be that nudges and placebos do not depend simply on trickery and deception, and can work in the light of day.

That鈥檚 not to say, though, that openness will be embraced by all. The next time you fill in a form online and see that a box has been checked by default, take a moment to consider if you really want to opt into that mailing list.