Hypothesis about autism.

[Buckeye_Democrat]

This is a very speculative idea on my part, but I wanted to share it here because I haven't seen it mentioned anywhere previously.

I was thinking about how society has changed since the industrial revolution, with many people asked to focus on the same job day after day, much more often than in prior times. It's an aspect of our world that I personally don't like because I get tired of doing the same things each day. People who work on a farm, on the other hand, have a broader set of concerns that keep their minds occupied in more diverse ways.

Then I considered evolution/natural selection. If some people are more adept at focusing on particular tasks, which our current economic system favors, shouldn't they be more likely to be "healthy" in that environment and reproduce? What would be the effect? Wouldn't their children also be more adept at focusing on particular interests?

That made me think of autism since it's a condition in which people tend to be overly focused on some objects and ideas to the detriment of others.

Hence, could the industrial revolution and division of labor cause greater rates of autism as time passes? If so, there should be higher rates of autism in more industrialized countries and in urban areas as opposed to rural areas.

When I Googled for such information, both were true!

Autism is more prevalent in industrialized countries (especially in Japan):
http://www.worldatlas.com/articles/countries-with-the-highest-rates-of-autism.html

Autism is more prevalent in urban areas:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2882422/

There might be other explanations, of course. Perhaps autism is more likely to be diagnosed in urban areas and in industrial countries? That seems very plausible too.

It just surprises me how often people overlook evolution and natural selection. It's a fact of life, and humans certainly aren't immune to the effects! People didn't remain dark-skinned when they left Africa for colder and less sunny climates because darker skin was a disadvantage in those conditions. With less sunlight and more clothing, lighter skin helped people create more Vitamin D from UV rays and they avoided rickets. Surviving to adulthood, they could mate with each other and produce lighter-skinned children.

In a similar way, our economic system acts as a selective pressure too. People who are pleased doing the same routines each day are more likely to be successful in that system, and those tendencies could also be passed down to their children. The ultimate result could be offspring with very strong focus, like children with autism.

Evolutionary processes don't always require long periods of time for the effects to be noticed. Look at the silver fox experiments that were done in Russia. When foxes with more human-friendly temperaments were mated, the result was fox offspring that were extremely friendly to humans. They started behaving like dogs!

[KT2000]

1. getting close -

In fetal development the first 3 months are the most critical for the formation of the brain. We are awash in a soup of chemicals that can alter that formation, sometimes by mimicking actual hormones such as thyroid. Sometimes the chemicals block the hormone, other times they act as the hormone in exaggerated ways - either way, development is affected.
The Industrial Age created pollution that has only become more complex.
Also - the worst damage from such exposures occur in subsequent generations of the individual exposed.

This is what is suspected by people who work in environmental health research but will never be proven to the satisfaction of regulatory agencies. Whatever adverse effects are happening as a result of our environment are the new normal.

[Buckeye_Democrat]

3. Finding such a cause would be nice...

since it would probably be easier to "correct" the condition if it's mostly caused by pollution/chemicals.

My very speculative idea would be more problematic because division of labor and specialization have resulted in greater efficiency for humanity in many ways.

I'm about the farthest thing from an expert on autism, by the way. I was mostly thinking about how our economic system might affect people over time through evolutionary processes, and greater focus/specialization was one of the selective pressures that I considered. That's one of the aspects that first came to my mind because I dislike it so much and I often feel like a "misfit" in this system -- e.g., picking majors in college (math and physics) when I'm actually curious about many subjects. It's not that I'm unable to focus or I couldn't have earned those degrees, but I haven't been very successful in this system partly because I don't want to spend most of my life thinking about the same subjects again and again.

In the meantime, I looked up the prevalence of autism among Native Americans because they've had less long-term exposure to industrialization compared to the Europeans and the Japanese and other groups around the world. They indeed have fewer cases of diagnosed autism. That certainly doesn't prove anything, but at least it seems to comply with the idea.

https://imfar.confex.com/imfar/2011/webprogram/Paper9515.html
the prevalence of identified cases of autism within the American Indian and Alaska Native population in California is much less than that observed for other ethnicities and lower than the expected rate.

[PoindexterOglethorpe]

2. I'm inclined to think there's not that much of an uptick

just a heck of a lot more diagnosing.

I have a son with Asperger's, and when we finally figured out that there was a name for his differences, lots of people I informed, when I told them the behavioral markers (difficulty making eye contact, obsessing on one topic, as children get along far better with adults than with other kids, an awkward gait when running, often extremely good at science and math, unable to understand social and body language cues) every so often someone would gasp and say, "That sounds exactly like great-uncle Joe!". They'd then go on to describe the relative and sure enough, he sounded like he probably was on the autism spectrum.

In the past people would institutionalize or hide at home family members who were too far outside normal. Special education at schools didn't really exist when I was in k-12. Up to about fifty years ago it was a lot easier for someone to leave school and be able to support themselves. Or, since there was no safety net for a very long time, to become some kind of drifter and just disappear.

These days, for all that we try to celebrate diversity, there is an overwhelming pressure to conform, especially so far as going to school is concerned. Children are expected to fit into little slots and not cause trouble. Those that do are often punished far out of keeping with the offense.

Had the diagnosis of Asperger's not existed, had my son been born fifty years earlier than he was, he'd have still had the same deficits, and would still have struggled mightily with school and socializing. Luckily, we were able to give him the support he needed and he's a reasonably successful adult at this point.

In short, you have an interesting hypothesis, but we don't have a sufficient handle on the incidence of autism going back several hundred or even thousands of years to be sure.

[Buckeye_Democrat]

4. That seems very plausible.

It wouldn't surprise me at all if that's the explanation. Careful statistical sampling over a diverse group of people with consistent diagnostic techniques would help settle the matter.

[Warpy]

5. Well, not so fast

Children in urban areas are certainly diagnosed more frequently because urban children have access to superior health care. Rural kids are lucky to see doctors who specialized in pediatrics and know how to detect autism in infants. Kids with severe autism are diagnosed when it fully presents, when the child is a toddler. Asperger's kids tend to fall through the cracks.

Remember also that early diagnosis of autism is a relatively new thing. When I was in school, kids with Asperger's, with dyslexia, and with other learning disabilities were all labaled "retarded," the then polite word for "slow" or "stupid"--how things change! Very high functioning Aspies were called nerds and geeks and weirdos.

What has evolved is the medical profession, not the children. Likely the farms used the labor of anyone they could, in any way they could, and it didn't make as much difference if a kid couldn't read or speak.

There are signs we're continuing to evolve as a species, just not over 300 years and not in that direction.

[phylny]

6. Don't overlook the role of pandemics changing DNA.

I read/watched something about the flu pandemic of 1918. If it didn't kill you, it may have changed DNA in subsequent generations.