People have wondered if play helps kids learn, but until recently there was little research that  explained or showed why it might be true. Where does pretending come in? It is what philosophers call counter factual thinking like what Einstein wondered what would happen if a train went at the speed of light.

In a study, three and four year olds were given a stuffed monkey and a musical toy and were told, “It’s Monkey’s birthday, and this is a birthday machine we can use to sing to Monkey. It plays Happy Birthday when you put a funny-looking object which was called a zando on it. Then she held up a different object and explained that it wasn’t a zando and therefore wouldn’t make the music play. Then she asked some tricky counter factual questions: If this zando wasn’t a zando, would the machine play music or not?” What if the non-zando was a zando? About half the kids answered correctly.

Then someone took away the toys and the kids were told that they could just pretend that one box is the machine and that a block was a zando and the other one wasn’t. They were told to put the blocks on the machine. So what happened next? About half the kids said the pretend zando made pretend music, while the pretend non-zando did nothing (well, pretend nothing, which is really quite a concept even if you’re older than three).

Studies showed that kids who were better at pretending could reason better about counter factuals and they were better at thinking about different possibilities. Thinking about these possibilities plays a important role in the latest understanding of knowing how kids learn. The idea is that kids at play are like small scientists testing theories. They imagine ways the world could possibly work and predict the pattern of data that would follow if their theories were true, and then compare that pattern with the pattern they actually see. Even the very young toddler turns out to be smarter than we would have thought if we ask them the questions in the right way.

Play is in the spotlight now, as parents and policymakers try to make preschools more like schools. But pretend play is not only important for kids; it’s a major  part of what makes all humans so smart.