It didn’t take much to persuade me that letting kids play is one of the great joys of parenthood. I’ve been known to send mine outside to “shovel” snow to earn their hot cocoa.

Most days, our living room couch forms the walls of a space shuttle or bear cave or restaurant I am privileged to patronize.

Then I stumbled upon a wonderful story in Scientific American that linked several studies that support the simple, retro child-rearing theory: Kids NEED to play freely.

When they do, they become smarter, less stressed and more resilient adults. And if they don’t, they may become anxious and maladjusted instead.

Wow.”Free play” is a different animal than the structured games or team sports like soccer that fill so many of our family’s schedules. Both offer learning experiences aplenty, but they have plenty of existing rules. Play doesn’t, so it encourages kids to create them as they go.

They learn to be flexible and communicate with each other to keep the play train moving down the track. Play is “a way in which children learn,”  Tufts University child development expert David Elkind says in the story, “and in the absence of play, children miss learning experiences.”

Luckily, it doesn’t take much to get started. The world outside our mudroom door is our favorite playground. There’s space to run and jump and roll like logs down the hill, and there are plenty of sticks to go around. Inside, all you need are a few great, natural toys—the simpler, the better.

One study suggested that a toy as simple as a box of blocks helped middle- and low-income toddlers score far higher on language tests than peers without them.That’s not to say that I don’t wince, at times, when I see my boys wrestling on the cushionless couch like bear cubs.

These sessions usually end in cries, which pulls me away from draining pasta or checking email. But as they’ve gotten older, I’ve started to ask them, “can you two settle this without me?” And, more and more often, they’re up for the challenge. (When they’re not, emails must wait.)

Of course, we don’t live in the wild. And, in civilization, tear-stained faces and rambunctious play can (and should) be avoided, right? Not so, says behavioral neuroscientist Sergio M. Pellis. Sure, the instinct to protect our children is natural. But so is free play—in all of its messy forms. ”

A child who has had a rich exposure to social play experiences is more likely to become an adult who can manage unpredictable social situations.”And in these unpredictable times, a little more play sounds like tonic for the soul.