Autism and Human Evolution

Although some traits of autism can be observed almost at birth (since we now know what we’re looking for), it is notable that it becomes most obvious around the age of two. This is, perhaps not coincidentally, when the first round of synaptic pruning and massive cell death occurs. This massive change in the developing toddler’s brain is why two-year-olds go through the “terrible twos.”

It is also notable that autistic brains show a lack of synaptic trimming. This results in an over-connected brain. Temple Grandin in Thinking in Pictures notes that autopsies of autistic individuals shows brains that look immature, particularly in the cerebellum and the limbic system, and that EEG scans show brain waves more typical of a 2-year-old’s (50), causing her to suggest that “autism is caused by immature brain development” (54).

If you think about it, if we were to understand the autistic brain as being the brain of a two-year-old’s that, nonetheless, manages to simultaneously mature in important ways, we can make sense of the traits of autism. Does a toddler understand what is and is not socially appropriate? How often do toddler’s embarrass their parents with their honestly and straightforward observations–including that the emperor has no clothes? Two-year-olds are infamous for their tantrums. Toddlers of course tend to be more literal and to not get metaphorical speech. Given the lack of language, it is almost certain toddlers are visual thinkers. When they do talk, their speech seems all over the place, even associative in nature. Toddlers expect everyone to be honest and kind. They don’t have fine motor skills. The senses have not yet become fully differentiated, meaning they experience a degree of synesthesia. Etc.

If you were to make a list of toddler traits and place it next to a list of autistics’ traits, the overlap would be overwhelming.

Coincidentally, there there is a second time when there is massive synaptic trimming, and that is during puberty. Lack of trimming during this time is associated with the onset of schizophrenia.

Lack of trimming up through the age of two gives you autism; lack of trimming through puberty gives you schizophrenia. This simultaneously suggests that the two are indeed related to each other, and at the same time that it is absolutely right to separate the two.

In the case of autism, what we see is a retention of infant/toddler traits as well as the development of new kinds of traits as the brain simultaneously develops and does not develop. The retention of infant traits in adults even as the adults mature is known as neoteny. And it’s not uncommon in nature. And it is particularly notable that neoteny seems to be a central part of great leaps in complexity in evolution. There is some evidence that humans are essentially a neotenous species of ape. And all vertebrates are neotenous sea squirts.

Does this mean that autism is a great leap in human evolution? It’s not impossible. That may be hard to believe given the difficulties involved with having autism, but it may also be true that there is nothing unmessy about evolutionary leaps in complexity. In fact, we know from the scientific/mathematical study of such leaps–known as catastrophe theory–that such transitions are both chaotic and often momentarily traumatic to the system. Which means that autism itself may not be the next stage in evolutionary complexity, but may perhaps be a stage to the next stage. Part of the evolutionary discovery process.

This could in part explain the gradual increase in cases of autism. I say gradual, because the apparent sharp increase is caused by a combination of redefinition and increased identification of autism in the population. At the same time, I’m willing to be there has been a real increase in cases over the past several millenia, or more. Again, this is what you would expect in an evolutionary discovery process.

The oddest thing about this potential leap into a new level of complexity is that it seems that people with autism are particularly well-adapted to computers and the internet. If I could manage to make a living only ever being online, I would probably never get offline. I communicate with far more people online than I do in the real world.

More, it seems that autistic brains actually work more like artificial neural nets than like neurotypical brains. I did a great deal of reading about ANNs when I was working on my Master’s in biology, and I continued reading about them over the years. I learned how they work, how they create concepts, and when I started reading about autism, I noticed almost immediately that the autistic brain works in almost the same way, create concepts in a bottom-up fashion in pretty much the same way. Also, if you read Temple Grandin’s book Thinking In Pictures, you will note that the way she describes the way she stores memories is much like a computer stores memories–exactly as seen/input. A computer cannot store information any other way. And as Grandin observed, “A severely autistic computer programmer once said that reading was “taking in information.” For me, it is like programming a computer” (38). I must admit to using the same language when talking about reading and learning new things–I refer to myself as an “information junkie.”

Come to think of it, given that people like Alan Turing were almost certainly autistic, it may be that the computer is a co-evolutionary product of autism. It may not be a coincidence that autistics are well-adapted to the very environment we (Alexander Graham Bell, Alan Turning, Bill Gates, and any number of computer programmers) created.

Advertisements

4 thoughts on “Autism and Human Evolution

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s