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Autism and Evolution

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Re: Autism and Evolution

#31

Post by scardine »

euyyn wrote: post #16
i14ng wrote: post #14

Earlier quoted context omitted.

When the autism diagnostic criteria were broadened in the DSM, the people making that change predicted that we would see this rise in diagnostic rates. That was the intent, to help a broader range of people. It's played out slowly as clinicians and schools were retrained. There's also been an increasing incentive to diagnose as autism in addition to intellectual disability when possible, because insurance companies a…

Can you give more details on the "some of them are obviously inherited, because the kids are so much like the parents" part? Kids everywhere are so much like their parents, so the reasoning, as written, is nonsense.

Families with one autistic child do have an increased risk of having a second child with the disorder.

There are some evidence that hints to genetic factors. For example, we know that boys are at much higher risk than girls, but we don't know why. Similarly, we know that older parents are more likely to have autistic children—but again, we don't know why.

See https://www.verywell.com/autism-4014759

Re: Autism and Evolution

#32

Post by CuriouslyC »

noipv4 wrote: post #17

So are Asperger / ASD mutations, a step back, step forward, or a step in a different direction (evolution?)

My guess is that the mutations are retained as variation in the population because having some small subset of them probably results in divergent thinking which can increase overall group survival. Autistic spectrum disorder individuals result from having too many of these mutations, such that neural activity patterns find a stable equilibrium outside of "normal" (think strange attractors in system dynamics).

Re: Autism and Evolution

#35

Post by jawarner »

adsfqwop wrote: post #4

I don't quite buy that autism will be shown to be genetic. I think it's an environmental factor. The rate of increase in autism is pretty much exponential: http://www.nature.com/news/2011/111102/full/479022a/box/1.ht... Now that's a very scary chart if you start to project that curve into the future. Here's another one. Not saying this is the cause, but it is a cause for concern. We have many similar patterns of envi…

I disagree, I find it intuitive that autism is genetic. View autism as a genetically induced alternate brain development. Usually it doesn't pan out, but sometimes it leads to innovation that wouldn't otherwise be possible. This leads to a survival advantage for a given subpopulation, which is sufficient for natural selection.

Re: Autism and Evolution

#37

Post by azakai »

slantedview wrote: post #34

There have been instances of biological twins where one winds up with autism and another doesn't. So to the extent that autism has a genetic component - it is just that - a component.

That does support non-genetic factors to some extent, but the existence of such twins matters less than their frequency, because twins don't always have identical DNA (mutations can occur after they separate).

Re: Autism and Evolution

#38

Post by azakai »

CuriouslyC wrote: post #32
noipv4 wrote: post #17

So are Asperger / ASD mutations, a step back, step forward, or a step in a different direction (evolution?)

My guess is that the mutations are retained as variation in the population because having some small subset of them probably results in divergent thinking which can increase overall group survival. Autistic spectrum disorder individuals result from having too many of these mutations, such that neural activity patterns find a stable equilibrium outside of "normal" (think strange attractors in system dynamics).

A reasonable theory, but as a minor note most evolutionary biologists wouldn't focus on group survival. Group selection remains controversial.

But your point still stands, and has clear parallels in other cases, like sickle-cell anemia: one copy of the gene is helpful, so it remains in the population, but two copies is harmful, so its spread is limited.

Re: Autism and Evolution

#39

Post by i14ng »

euyyn wrote: post #16
i14ng wrote: post #14

Earlier quoted context omitted.

When the autism diagnostic criteria were broadened in the DSM, the people making that change predicted that we would see this rise in diagnostic rates. That was the intent, to help a broader range of people. It's played out slowly as clinicians and schools were retrained. There's also been an increasing incentive to diagnose as autism in addition to intellectual disability when possible, because insurance companies a…

Can you give more details on the "some of them are obviously inherited, because the kids are so much like the parents" part? Kids everywhere are so much like their parents, so the reasoning, as written, is nonsense.

Kids often share autistic traits with their parents. The parents are either diagnosable themselves or very nearly so.

My son is the third or fourth generation to be likely-diagnosable, for example.

Currently-middle-aged parents without intellectual disability had almost zero chance of being diagnosed as children, because when we were kids autism was defined such that you usually had to be nonverbal or intellectually disabled to qualify.

A very commonly-reported experience is for parents to be diagnosed after their children are diagnosed.

Re: Autism and Evolution

#40

Post by cmiles74 »

kijin wrote: post #13
3pt14159 wrote: post #8

Earlier quoted context omitted.

My cousin had debilitating autism that was greatly diminished by removing wheat germ from his diet, so I partially buy the environmental take, but on the other hand it is a disease that is correlated with parental IQ, where a higher IQ leads to more likely incidence of autism. I don't think it's a coincidence that the rise of co-sexed secondary education and finer grained sorting with institutions like Harvard and MI…

Since this thread is about evolution, we might even say that the evolutionary pressures we currently face in the developed world actually favor mild variants of ASD. It might be because some ASD traits help people become more successful in the information economy. Asperger's people often thrive in well-paid occupations such as programming and data analysis where spontaneous social interaction is widely acknowledged t…

I have not seen any evidence that Asperger Syndrome or mild autism leads to well-paid occupations. For sure, there is some anecdotal evidence (which I find unconvincing), but I haven't come across anything more solid, like a research paper or study. If you've seen something along those lines, please post a link.

I do believe that children with Asperger Syndrome often see the symptoms grow less severe as they age. Perhaps with lots of hard work and a good support structure, some of them people grow to enjoy above average success. It seems entirely unreasonable (and to my mind somewhat cruel) to credit this success to Asperger Syndrome itself.

https://en.wikipedia.org/wiki/Asperger_syndrome

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