By Steven Schlozman, MD

Posted in: Grade School, Pre-School

Topics: Child + Adolescent Development

Let’s talk about rats with toys, and rats without.

In fact, let’s put rats on hold for a moment. Let’s talk first about children’s museums; that’ll take us to rats and their toys, and move us nicely to the welfare of the brains of our children. The story goes like this:

Anyone who has been a kid and now has one knows that children’s museums have been changing. What often began as tired wings of more-adult institutions, now have their own buildings and names (the Boston Children’s Museum, for example), and their own “stuff.”

Parents often view these younger establishments with a mixture of dread and relief. Turn your kids loose! Every display cries out for this kind of freedom.

But wait. Where the hell is my kid? And who is that ill-behaved little imp who just elbowed that sweet curly-haired toddler in the kidney? Where are his parents? And, would someone please tell me why, in this age of drug-resistant bacteria, would anyone choose to design a place where children can crawl all over each other and leave trails of snot the way a snail marks his progress across the sidewalk?

I’ll admit that I still to some extent see children’s museums as one giant Petri dish, a happy place for viruses, bacteria and a select few multi-cellular microbes to party.  The humans are the ecosystem, the paradise for a bunch of nasty contagions. And yet, every weekend, tired parents and their wheezing progeny line up before these museums even open, pushing their way in like they’re about to see The Who in concert, providing new and exciting homes for the mass of germs that lay in wait, like trap-door spiders, for the first little hand to move them to some new organic material. The circle of life is like this.

At our local children’s museum recently, I set my children free.  My daughter unraveled from her backpack like a mummy eager to leave the darkness of his tomb, and off she went, climbing the fantastical web-like structure that is the centerpiece of the Boston Children’s Museum.  Kids disappeared and reappeared ten feet above, elbowing, clawing, climbing and moving. They had no real purpose except to move from one stage to the next. And, undeniably, they were ecstatically happy.

I found myself marveling that they volunteered for this. Even more so, that they crave it—more than I crave my morning coffee. And, as a guy who likes to think about brains, I also had to remind myself of the incredible process to which I was now being treated. I was watching little brains become big ones. I was watching, in vivo, neurogenesis.

So now, let’s talk about rats.

For years, rats have had the misfortune of being laboratory animals with brains just big enough to be studied. In college, I lived in a co-op with a woman who practiced Wicca. She had sprung a rat from the school biology lab, and carried him around on her shoulders. He was named after an African god whose title escapes me, but I still remember that wonderful white beast clinging to his mistress’s hair and collarbone, and running down her left arm to eat at the table with the rest of us at dinner. He looked at us thoughtfully, with every suggestion that he enjoyed his thoughts, and he grasped his little piece of bread in his hands not unlike a toddler, nibbling wisely with his mouth open. This was not a dumb animal.

His friends, though, faced worse fates. A charitable narrative for his cousins involved life in the animal behavior labs rather than the medical research ones. This would mean an endless and increasingly complex array of mazes to negotiate, and then, as befits the noble fate of many lab animals, the insensitive and blunt probing into how his brain changes after mastering the maze itself.  Unfortunately, this often involved a high-tech blender, which to this day creates conflicts for me. But, that is the subject for another blog.

Here’s what was discovered, and keep in mind that this is hardly surprising, and therefore not the punch line of the story—rats that spend their days in mazes have bigger and more robust brains than rats that sit around in sterile laboratory cages all day. They especially enjoy neuronal growth in the frontal lobes (the executive regions of the brain), the places they go to biologically when it’s time to solve problems. Makes sense, doesn’t it? If you spend all day solving puzzles, your brain is likely to grow to accommodate the changing environment. That’s what neuroplasticity is all about.

But, what if it isn’t the maze per se that causes their brains to grow? And, what if the optimal time for growth is limited? It turns out that older rats that run mazes don’t learn as quickly, and their brains are less likely to morph for the better. This is consistent with what we know about brain injuries in general. Younger patients recover function more quickly, their childish brains more willing and able to bend from their original tasks.

So, here is the punch line: the maze matters, but not nearly as much as the running around itself. Free-form play, also known as the exploration of novel stimuli (and basically the equivalent of recess at a grade school without rules), correlates with the most neuronal growth of all. It isn’t the maze; it’s the act of playing, non-directive playing, that makes the difference.

It’s the germ-laden, web-like climbing structure in the Boston Children’s Museum that makes our kids happiest, and, more importantly, that makes our kids’ brains grow like dandelions in a June front lawn. The museum’s web-like climbing structure is way cool…and our kids crave way cool. You can almost see their little dendrites and axons talking.

So, let’s wrap up by considering the rest of the life of a child. In fact, this story could be all about policy. My daughter goes to a wonderful school where recess is preserved—there are cool things to climb on, monkey bars to master (she broke her wrist on the monkey bars while demonstrating her simian prowess to her friends), and slides to race down and around. Rules are generated by the children, for the children, and we know from the rats that this is what makes their brains happy.

Increasingly, however, we stifle recess, organize activities, schedule play, and mandate fun. We take the rats out of the cages with cool stuff, and put them back in the boring mazes. It’s better than the cages where they can only eat and sleep, but not by much. The social forces that propel such intensely-organized activities have been much discussed, but think for a moment: how incredible yet sad that we have not worked harder to preserve the deceptively simple and optimal setting for the brains of our children. The science is there to support the loosening of the reigns; let’s hope that the policy follows.

A version of this post originally appeared and was written by the author (Schlozman) on Psychology Today’s online site in 2009.