Have you ever met an orangutan with attention-deficit/hyperactivity disorder (ADHD)? I haven’t. But what do you think would happen if you dressed one up in jeans and a tee-shirt, put him on a school bus, sent him to kindergarten, handed him a pencil, and told him to sit quietly in his seat and do a geometry worksheet? I bet he’d seem easily distracted, make careless mistakes, seem not to listen when spoken to directly, have trouble sustaining his attention, have difficulty sitting still, and try to leave his seat before he finished his work. During recess, I bet he’d have trouble playing quietly, have a difficult time waiting his turn, and intrude into others’ games. These are common symptoms of ADHD, and if you sent him to the doctor, I bet he’d come home with a prescription for Ritalin.

No animal other than us modern humans—our hunter-gatherer ancestors included—suffers ADHD. But plenty of today’s elementary school children, who spend eight hours a day jammed inside a classroom, do. The American Psychiatric Association considers it a mental disorder. But it is also exactly what you’d expect if you put any juvenile (insert your choice of species here) behind a desk, made it do seatwork, told it to concentrate, and didn’t let it out to play.

Today, nearly 10 percent of children (5.4 million) in the United States have been diagnosed with ADHD. The percentage of ADHD diagnoses has increased an average of 3 percent per year from 1997 to 2006, and an average of 5.5 percent per year between 2003 and 2007. People have blamed the rise in ADHD on everything from television sets to pesticides, from head injuries to food allergies, from bad genes to terrible parenting. But you know what’s really not good for children who still have a limited ability to sustain their attention and healthy appetite for rambunctious play? Stuffing them into a classroom for eight hours a day.

If you’ve ever spent any serious time with young children, you know that they simply have trouble paying close and sustained attention. You also know that their play can be vigorous if not raucous at times. Such tendencies, especially among boys, don’t fit well with hours of sitting quietly in seats, minding one’s own business, and concentrating on desk work. Yet schools generally discourage children’s natural active tendencies, which has made a growing number of evolutionary scientists wonder whether much of the disruptive behavior might simply be due to children’s naturally limited attention spans and their natural drive to play actively, explore, and socialize.

This raises the possibility that some unknown percentage of children has been misdiagnosed with ADHD simply because they are naturally active and have a natural desire to explore and engage in social play. Of course, highly active, attention-shifting children, even when not the most extreme, can be disruptive to a classroom. But perhaps the classroom setting shares some of the blame. You wouldn’t take a recovering alcoholic—someone with a drive to drink—to a barroom and then ask him not to have a gin and tonic. So why put children—youngsters who can’t help but shift their attention and be rowdy—in a classroom and ask them to sustain their attention and be sedentary for long periods of time? Wouldn’t that make you an enabler?

Now I’m not trying to argue that ADHD isn’t a real condition or that it is merely an artifact of the classroom. But that perhaps some restless, rambunctious children have been misdiagnosed. In any given kindergarten class, those children born just before the cutoff date (that is, those who are young for their grade) are more likely to be diagnosed with ADHD (and prescribed psychostimulant medication) than those born just after the cutoff (those who are old for their grade). Because there is no reason to suspect that incidence rates in any given year would be greater than any other, these findings provide compelling support for the idea that a mismatch between the demands of the classroom and children’s typical behaviors have led to some degree of overdiagnosis. The assumption is that the younger children’s more immature behavior made them more likely to be tagged as having ADHD.

This overdiagnosis might not seem like a big deal until I tell you that over half of all children diagnosed with ADHD take medication, usually Ritalin, to control their symptoms. These 2.7 million children represent nearly 5 percent of children nationwide; the highest rate of any country in the world. Ritalin, a psychostimulant, works well to reduce impulsive behavior. But Ritalin also might quell children’s natural desire to play—which is the business of childhood. A burgeoning literature tells us that abundant play is important for the normal development of a range of social and cognitive skills. It is through play with peers that children build important abilities, like effective communication, perspective taking, and self-regulation. Research also demonstrates that free play can reduce stress, improve working memory, and boost attention span. In short, play makes children sharper, better behaved, and more socially competent.

In fact, there is growing evidence that more play might be part of the solution—or at least a better solution than psychostimulant drugs—for children diagnosed with ADHD. Jaak Panksepp, a behavioral neuroscientist at Washington State University, created a rat model of ADHD (by destroying the right frontal cortex—the region of the brain responsible for paying attention, planning ahead, and being sensitive to social cues). This model should translate to humans because children diagnosed with ADHD often have delayed frontal lobe development. When he observed these rats playing, he discovered that they had more overall activity and engaged in more rough-and-tumble play than rats with intact brains. So the rats with damaged frontal cortices not only had brains like children with ADHD but also behaved hyperactively like them. Then Panksepp gave his ADHD rats extra opportunities to play—which generally took the form of play-fighting—and their behavior later showed reduced hyperactivity.

Do Panksepp’s findings mean that extra play can reduce ADHD symptoms in children? That work still needs to be done. There is, however, some evidence from studies done by education psychologist Anthony Pellegrini that show that recess breaks reduce children’s fidgeting in their seats and improves their ability to pay sustained attention to academic tasks—two dimensions of ADHD. So there’s likely no harm in treating children’s inattention and hyperactivity with a recess break before we ask for a prescription of Ritalin.

Other work from researchers at the Human-Environment Research Lab at the University of Illinois indicates that time spent in natural outdoor settings can reduce the symptoms of ADHD in children. The argument goes that artificial environments like city streets, living rooms, and the classroom exploit crucial weak spots of the brain. They’re so overstuffed with stimuli that children (and adults) need to constantly work to redirect their attention so that they aren’t distracted by irrelevant things, like the girl who is poking her classmates’ arms, the boy who is singing his ABCs, the grinding of the pencil sharpener, the classroom guinea pigs squeaking for attention, the box of crayons that fell onto the floor, and the principal reprimanding the bullies in the hallway. To do anything in these sorts of environments, children need to use “controlled perception.” They need to constantly tell their brains what to pay attention to and what to ignore. But ignoring so many constant sights and sounds takes a lot of energy and effort, and consequently it requires a lot of brain power. This is a very difficult task for children because their attentional abilities are not yet as mature and smoothly tuned as adults’ are.

Natural settings, in contrast, don’t require the same amount of cognitive effort as artificial environments. University of Michigan psychologist Stephen Kaplan thinks that the outdoors—because it’s made up of natural stimulation rather than artificial distractions—can have a restorative effect on attention. The brain machinery we use to ignore telemarketing phone calls, infomercials, and junk emails can relax deeply and replenish itself when it is surrounding by nature.

There’s also the idea that artificial environments don’t just deplete attention but also interfere with self-control. When a first grader is sitting in his seat trying to work quietly on his math assessment, his brain is assaulted with temptations—the computer word game his classmate is playing, the joke the new kid is whispering, the cherry bubble gum in his jeans pocket, the juicy note that his best friend just passed, and his new gaming console peeking out of his backpack. To resist these temptations he needs to involve his prefrontal cortex—the very same region that has already been taxed all day at school as he tried to focus on his deskwork. Because his brain has been barraged all day with such demands, it is less able to garner the neural resources to exert self-control and consequently his brain is likely to give in to the joke, the note, or the bubble gum.

This is pretty much the double whammy of the modern school building. Children’s overstuffed classrooms subvert their ability to resist the temptations of these same overstuffed classrooms. The result is that children’s brains can too easily short circuit. As parents and teachers, I don’t think that we take the fragility of children’s attention serious enough—it is something we should protect and try to replenish with play and nature experience rather than jump to medicate.

Adapted from Your Brain on Childhood: The Unexpected Side Effects of Classrooms, Ballparks, Family Rooms, and the Minivan (Prometheus, 2011),