The Frontal Cortex

Over at Slate, Gregg Easterbrook proposes an audacious hypothesis: the rise of television viewing among infants is responsible for the current autism epidemic.

The idea is wholly speculative. No scientist has shown a link between autism and television, but so far as I could determine no scientist is working on this question, either--and maybe someone should be. Beginning in about 1980, TV watching in early childhood began to rise, coincident with the proliferation of affordable VCRs and cable channels offering nonstop cartoons and kids' shows. The child's brain is self-organizing in the first few years of life, and visual stimuli have much to do with how it organizes. Humans evolved while responding to three-dimensional visual stimuli. The advent of ubiquitous TV for young kids amounts to an unplanned experiment that exposes developing brains to tremendous doses of colorful, moving, two-dimensional visual stimuli. Coincident with this experiment, there has been a sharp rise in the number of children who, through autism, lose their ability to relate to the three-dimensional, normal world.

Easterbrook's hypothesis isn't as crazy as it seems, although I think he focuses on all the wrong symptoms. In his article, he stresses the two-dimensional nature of TV, as if autism was simply a matter of bad depth perception. He also focuses on problems with the visual cortex, but vision seems to be one of the few mental capacities that aren't affected by autism.

So how might TV be a cause of autism? (Keep in mind that my speculation, like Easterbrook's, has no basis in fact or experiment. It is pure hypothesis, or what my boss used to call "unempirical bullshit".) First, we should have a clear sense of what the core symptoms of autism actually are. While this remains a controversial topic, most scientists define autism in terms of a child's social and emotional isolation. ("Aut" is Greek for "self," and autism translates as "the state of being unto one's self." When Dr. Leo Kanner first diagnosed a group of eleven children as autistic in 1943, he described the syndrome as one of "extreme aloneness.")

In recent years, neuroscientists have discovered a possible source of this emotional isolation: a faulty mirror neuron system. When most of us watch a face express an emotion, our mirror neurons light up as if our own face was expressing that same emotion. This leads us to instinctively empathize with others. Autistics don't make this connection. They see the angry face as nothing but a set of flexed facial muscles. A happy face is simply a different set of muscles. But neither expression is correlated with an emotional state. Autistics are blind to the minds of others.

Although emotional isolation remains the defining characteristic of autism, autistic children also display a wide spectrum of other symptoms. The elegance of the mirror neuron hypothesis is that it provides likely explanations for these seemingly disconnected deficits. As psychologist Hugo Theoret observes, "If you imagine the behavioral and social deficits that would come from a failure of the mirror neurons, you imagine a pathology just like autism." For example, mirror neurons provide a simple anatomical source for one of the more perplexing symptoms of autistic children: their lack of motor coordination. Mirror neurons are located in our motor cortex, and help us learn and master physical movements. Autistic children seem to lack this ability, and learning new physical activities remains deeply frustrating. Mirror neurons have also been implicated in the development of language, an anatomical fact that seems to explain the severe linguistic impairments of autistic children. (Please remember that the connection between mirror neurons and autism remains very tentative.)

So how might TV be one of the causes of the "autism epidemic"? To be honest, I have no idea, and neither does Gregg Easterbrook. But a possible answer focuses on the way the newborn brain organizes itself in response to the stimuli it receives. If an infant's world is suffused with cartoons and television shows instead of normal human interaction, then it wouldn't be so outlandish to imagine a brain that is ill-equipped at understanding and interpreting other people. In other words, autistic children are bad at generating a theory of other people's minds because they didn't have very much practice at it. Their mirror neuron systems missed some critical period of experience.

Sounds silly, right? It probably is. Nevertheless, we shouldn't forget that scientists used to think that babies didn't need a loving touch. Now we know better. Infants deprived of cuddling never recover. It's remotely possible that a similar phenomenon occurs with visual stimuli. Brains exposed to cartoons instead of three-dimensional facial expressions might be permanently altered.

Needless to say, my hypothesis has too many caveats to count. For starters, we should resist ever suggesting that autism is simply caused by some aspect of parenting. (This was Bruno Bettelheim's terrible mistake.) Such oversimplifications always do more harm than good. The fact is, autism is a terribly complicated syndrome, and consists of a wide spectrum of symptoms, many of which probably have different causes. (If I were a betting man, I'd wager that in a few decades we'll realize that what we now call autism is actually several different diseases.) That said, I sure wish some scientists would look into Easterbrook's outlandish idea. Even if TV only has some very minor effects on the development of mirror neurons in children, such a finding would have profound implications.