Why we found that over the next several weeks, those who had been consuming

An average is an instruction pretending to be arithmetic. Tell heavy energy users that their neighbours consume less and they may improve. Tell the efficient households exactly the same thing and some discover they have been behaving like mugs. The benchmark made the middle respectable.

Watch authorities pay to spread their own bad habits. A road sign announces that one in three drivers speeds here, creating a locally targeted advert for speeding. A school tells parents that most pupils miss homework occasionally and the conscientious family relaxes. A hotel asking guests to reuse towels reports that most previous occupants did so; now the appeal comes with a crowd rather than a lecture. The efficient minority needs a different signal: approval that says, in effect, “yes, your extra effort counts; please carry on.” Numbers about other people answer a question nobody necessarily asked: what will make me look normal?

Broadcasting a norm therefore changes the thing being measured. Think about both sides of the average. Who should move towards it? Who already performs better? Approval can stop the better group sliding backwards. Where the average is dreadful, point to the standard worth reaching or the growing number already reaching it. A giant reassurance that failure has plenty of company will also work, just in the wrong direction. “Most people do this” has power. If “this” is rubbish, shut up about its popularity.

Behavioural principles

Behavioural ideas at play in this post

Short, plain-English explanations of the principles behind this post, with links to related books and examples in the archive.