In 1997, Boston ran an unintentional randomized control trial. The city had decided to offer free pre-school for all of its residents, but there weren't enough spots for everyone that applied. The city used a lottery to decide who got in. Researchers looked at the results 20 years later. Those who had been accepted to the free preschools didn't do better on standardized tests in elementary school and middle school. But preschool did have some effects. Those who had been accepted were more likely to graduate from high school, take the SAT, and go to college. They were less likely to be suspended or incarcerated.

Often times we're confronted with the choice between work and play. We optimize for work that has more certain and immediate payoffs. Play seems valuable if it opens up new pathways for work, for example, learning how to code may open up new career opportunities. But rarely do we think of play as valuable on its own, even if we run into dead ends. What the Boston preschool experiment teaches us is that a mind at play is valuable on its own, not for the obvious reasons, but for building a resilience and grit that we might not get otherwise.

p.s. The title of this post, A Mind at Play, is taken from a book on Claude Shannon, the father of Information Theory. He had many hobbies: juggling, unicycling, chess, a flame-throwing trumpet, and devices that could help him win at roulette and solve a Rubik's cube.