Autism, literacy, and natural selection

I stayed up past my bedtime last night, engrossed in Paul Colllins’s Not Even Wrong, which intercuts a memoir of his discovery of his son’s autism with a history of the condition. Collins is kind of a historical magpie. He puts into his book everything from the story of Peter the Wild Boy—found in the woods of Hamelin, Germany, in the eighteenth century and adopted by George I of England—to the nastiness and imposture of Bruno Bettelheim.

Some of the bright, shiny facts collected by Collins started me on a speculation. Autism comes in different levels of severity, and it seems to be heritable. In the 1943 article where he first described autism, Hans Asperger noted that “We have been able to discern related incipient traits in the parents or relatives in every single case” (p. 90). Collins inventories proto-autistic traits in himself, his wife, and their parents: enthusiastic list-making, fascination with texts and systems, attention so narrow that it causes “selective hearing.” He talks to researchers who have found a high incidence of autism in the children of engineers. When he gives a talk at Microsoft, Collins is surprised that many in the audience seem to be playing with their laptops instead of listening to him. It turns out they are listening to him but prefer to do it via the company’s internal webcast.

All this set me wondering. There’s been a lot of concern recently that the incidence of autism seems to be rising. Some have put the blame on the mercury-based preservatives in vaccines given to children, but a government panel last week found no link. (Collins hasn’t mentiioned this yet, but like I said, I’m only halfway through.) What if the cause is something else entirely? What if it’s assortative mating?

In other words, what if the premium that the information economy puts on cognitive skills and the advent of the two-career marriage has created a new situation, in which people with mild proto-autistic behaviors are more likely than ever to find each other and wed? This is a bit wacky as a hypothesis, because I’m suggesting more or less that the mind is evolving, observably, in response to extremely new conditions. But assortative mating is a powerful force. And actually, the premium on literacy (and the behaviors that enhance it, such as intense focus and comfort with solitude) has been in place for several centuries now.

College, in this light, would be a breeding ground for autism, because it encourages people who score well on standardized tests to socialize and mate with one another. So would places like Silicon Valley, Seattle, and the Greater Boston area, because the computer industry brings together people with proto-autistic traits in unprecedented concentrations.

I also wonder, sometimes, whether a high rate of depression in the modern world might be a side effect of a premium on literacy. Humans weren’t originally built to sit still for long periods of time while paying close attention to inanimate objects. They were built to pay close attention while pursuing their four-legged dinner, or while conversing with other humans. Some evolutionary psychologists think that depression was originally designed as a “shutdown” mode to detach a person from a task that looked as if it would be unsuccessful. What if it turned out to have an unforeseen second use in a literate world, because it made a person willing to sit still at length, in isolation? It could be that the genetic innovation that would isolate this boon from the other traits associated with depression (dysphoria, suicidal ideation, etc.) hasn’t yet arrived, and we’re stuck with a situation where people who like to read are also people prone to depression. Of course, it could be that the human temperament hasn’t changed at all, but that when humans are encouraged to sit still for long periods, they become prone to depression. (I think there’s a paper to be written by some enterprising experimental psychologist on the relation between webpage-loading time and perception of self-esteem. Between two people, a delay in response is usually perceived as a slight, and a human who’s browsing the internet must, at some precognitive level, perceive its responsiveness to him as a measure of his social status.)