Koerner says with Let Grow, kids discover skills and abilities they didn’t know they had. And they also discover what it’s like to fail. While on the surface might not sound all that appealing, failure is how kids learn how to overcome obstacles, try out new ideas, and become resilient. It’s also how adults learn as well — ask any CEO.)

“If we don’t offer them these opportunities to communicate, to collaborate, to problem-solve, then how can they be successful in a global society?” Koerner asks.

According to psychologists, that’s an important question. Dr. Peter Gray, research professor at Boston College who focuses on child play, says that erring on the side of caution isn’t helping children. By trying to give kids a leg up, scheduling every free minute with karate or Little League or music lessons, parents are in fact doing them enormous harm.

Gray says that over the past 50 years, as we’ve seen a decline in children’s freedom, we’ve seen an increase in responses on standardized questionnaires that indicate both depression and anxiety disorders. Specifically, an eight-fold increase on depression, and five-to-ten-fold increase on generalized anxiety disorder. Gray notes that this is just a correlation, and he’s looked at many possible explanations.

“It doesn’t correlate with economic cycles, wars, or divorce rates. But it correlates very well with the decline of children’s freedom to play.”