"It'll go to their head"

The last defence of the drawer is that saying the good thing would do harm. Your teenager would coast. Your colleague would stop trying. The person under you at work would think they'd arrived, and the next piece of work would be worse. In this belief, a good opinion kept in is a standard kept up, and praise is what you give people when you've stopped expecting anything.

Let me look at what the evidence says about what a kind word does to effort, because it points the other way. Deci, Koestner and Ryan, three researchers on motivation, published a meta-analysis in 1999 that pulled together 128 experiments on rewards and what they do to people's interest in a task. The headline was that tangible rewards, money and prizes, tended to reduce how much people did a task when they were free to stop. But positive feedback, being told you'd done well, did the opposite. It raised both how long people kept going by choice and how interested they said they were. One caveat from the same paper is that the effect was weaker for children than for students, and I'll come back to children in chapter 20.

There's a workplace version too. Christiane Bradler, Robert Dur, Susanne Neckermann and Arjan Non ran a field experiment, published in 2016, with more than three hundred workers hired for a three-hour data-entry job. In some groups, after two hours, workers unexpectedly got public recognition for their work. Performance in the third hour went up. The part I find most interesting is where the rise came from. Most of it came from the workers who hadn't been recognised. Recognition in the room lifted the room, not just the person it was aimed at.

I'd be careful with both. A lab meta-analysis and a three-hour data-entry task are not your teenager or your team. What they rule out is the mechanism the belief needs, which is that a good word makes people stop. Across a lot of experiments, being told you'd done well made people do more, not less.

The word doing the damage here is "praise", and I'd drop it for adults. Praise is a grade, handed down. A compliment between adults isn't a grade. It's one person's report of what they saw, and nobody stops working because a colleague said their slides were clear. What people coast on, in my experience, is not knowing whether anything they do is noticed at all. The drawer doesn't hold a standard up. It just makes sure nobody can tell what the standard is.