What role did autism play in human evolution?

http://www.sapiens.org/evolution/autism-human-evolution/

by sajid • 9 years ago

31 53 9 years ago

nv-vn2• 9 years ago

Probably none? A gene doesn't have to be beneficial to stay in the gene pool. A lot of this seems like a stretch. This isn't in any way meant to say that autistic people aren't useful members of society, but claiming that autism is some advantage doesn't have any real backing to it as far as I can tell. It's no surprise that all the people interviewed in the article are autism specialists. I don't think most other researchers would see the same things looking at the data.

dwringer2• 9 years ago

"A gene" ... what gene? The article itself states:

we are all “a bit autistic,” and we all fit somewhere along a spectrum of traits.

whatshisface• 9 years ago

You might want to loosen up your interpretation a bit to understand his point - if a gene doesn't have to be beneficial to say in the gene pool, then a vague blob of thousands of genes doesn't have to be beneficial either.

samhain• 9 years ago

I like your point, saying that genes don't need to be beneficial to stay in our DNA. (after all, our DNA has huge swaths of repetitive or inactive codes interspersed between protein coding instructions) To say that it has -no- influence on human evolution is unlikely, given that it is takes a combination of genes that result in the expression. Those combinations on their own influence brain development via encoding of proteins at certain times of development, or switching other genes on an off. Perhaps the expression of ASD isn't very influential on human evolution, but to say that it isn't -at all- related, or that it's constituent genes have no affect on our development is likely incorrect.

nv-vn2• 9 years ago

Yeah, my comment might have tried to make the situation sound a bit more absolute than what I actually mean. I do believe that there likely was some effect, but there was no major effect that made autism some net-beneficial improvement (or else the majority of the population would have it). It might be true that certain autistic tendencies can be a net-win for the gene pool (these would probably just be seen as "normal human behavior" by now, though, since they would have accumulated in most of the gene pool unless autism developed relatively recently (probably not the case considering people from every continent have been diagnosed)). I also don't think that it was a net-negative, or at least not by a significant amount. It could be that at one point autism was more prevalent and then this changed (which would make it probably a net-negative), but my guess is that it's a relatively average trait (in that it won't cause a major fluctuation in either direction in terms of breeding). That said, it seems pretty reasonable to say that (being a spectrum and all), more "severe" diagnoses of autism would result in a lower chance of breeding. Slightly-autistic people probably had an above average survival rate with a relatively low change in fertility, but people with severe autism are and were less likely to have children, so it's likely gone down. At the end of the day though, it's not too far off from other mutations like hair/eye color (which make a small difference in the reproductive weight, but not enough to completely take over the gene pool and knock out the competing adaptations).

louithethrid• 9 years ago

It could be a usefull specialisation for a medieval society needing automatization.

Not every specialisations usefullness is instantly obvious under the very artifical circumstances of a heavy industrialized society.

Beeing a warlord was usefull for many centurys, but today it only gets you into a CEO chair and stomache ulcers. Shizophrenia was a good trait for aeons, when it came to beeing a priest/shaman, a artist or simply some loner hunter, who could follow prey for weeks without the onslaught of isolation anxiety.

Nothing of this usefullness can be glimpsed today. In addition - autism seems to manifest itself mostly in the west, so maybee its really new - and its ability to pay the ferrywomans price, directly or indirectly, has yet to be established in societys under crisis.

ShabbosGoy• 9 years ago

Shizophrenia was a good trait for aeons, when it came to beeing a priest/shaman, a artist or simply some loner hunter, who could follow prey for weeks without the onslaught of isolation anxiety.

I'm not sure how useful schizophrenia would be as a hunter. Being a hunter requires a high degree of inhibitory control and some level of metacognitive ability. Wouldn't constantly hearing voices all the time distract the hunter from hunting and tracking his prey down?

qb453• 9 years ago

Hunter maybe not, but if African shamans themselves apparently recognize schizophrenics as their own then there could be something to it:

http://www.jaysongaddis.com/the-shamanic-view-of-mental-illn...

sdiupIGPWEfh• 9 years ago

My only half-serious musing is that, as with autism, we're all somewhere on the schizophrenic spectrum, in some sense. Hearing one voice in your head is a step above hearing none. Having multiple voices, sourced from different subconscious processes, yet only heard one a time and that you can't distinguish between thus perceiving as a single "you", might be a step above just one.

gaius• 9 years ago

Not really, medieval period to now is too short a timescale for evolution to operate

watwut7• 9 years ago

Warlords needed to actually fight and be strong physically. Not really the same as being CEO.

TomasEkeli• 9 years ago

The autists I know of have no special skills or magical insights. They're really struggling to get through normal days, requiring constant supervision from full-time carers 24 hours. And it has to be the same carers that come at the same time every day. Their lives are really shitty, interspersed with small joys.

poizan422• 9 years ago

Well, sounds like the only people you know to be autistic are low functional...

Traits that may be beneficial in milder versions can often be detrimental if too expressed. If you are working with software developers then there's a good chance that some of your colleagues falls on the spectrum. It's probably not something they go around telling people about, assuming they are even themselves aware.

douche• 9 years ago

I sometimes wonder if we sometimes self-label ourselves, in general, as being "on the spectrum" just so we can justify getting pissy when uninteresting people interrupt and harass us while we are trying to concentrate on interesting problems.

bad_user2• 9 years ago

I think claims about "the spectrum" are often overblown. Most software developers do not exhibit any traits linked to autism.

watwut7• 9 years ago

People like to overstate amount of people on the spectrum in programming - and it likely went down as it gained popularity. High functioning autistic are easy bullying target for "alfa geeks" and can't really cope well in companies where culture fit is important. They also have harder time coping with time pressure, working in open space (noise, disruptions), tight agile cooperation (this is two sided hell), have hard time controlling emotions (go into rage), have hard time deal with changes of plans, unexpected and plenty of other situations currently present.

I guess it is less bad for them to be in programming then in marketing, but normals still have it better.

Also, they are good in some thigs - great with routine, rarely make mistake, rarely inattentive, great memory. Then again, as a rule, they have less good abstract thinking which limits them a lot, goes into rage because programmer on unrelated project used slightly different code style.

If we are talking about people who are normally diagnosable, diagnosis is not exactly shock for people who work with them. You may not be able to guess diagnosis, but you are aware that the person is off.

danellis• 9 years ago

What do they need supervision of? Perhaps they're things they wouldn't have been expected to do on their own a few thousand years ago anyway. Perhaps they would have had an easier time in an early, small human community.

watwut7• 9 years ago

Low functioning autism may mean "bangs head on the table even as blood goes out because routine got interrupted - favourite ipod run out of batteries". Or "goes into epic rage because the cup is not on exact same place as usually - it is 15cm on the left in the same drawer. "

It is serious condition. Most would simply die young.

sajid• 9 years ago

I think the argument is that although autism itself might be detrimental, the broad autism phenotype may have proved beneficial in human history.

grandalf• 9 years ago

The autists I know of have no special skills or magical insights

This is not necessarily a counter-argument since it is limited to the sample size of those you know.

The argument supposes that there would be enough benefit to the upside traits of autism disorders to keep the genes in the gene pool.

Also, it's not clear how the genes work or how the spectrum of autism-related conditions might have offered beneficial side-effects to group survival.

Interestingly, I think it follows that only in animals with "culture" would we find such selection. I wonder if it occurs in dolphins or primates, etc.

blunte2• 9 years ago

And quite possibly they have some unrecognized or under(non)represented great skills.

Consider how we as humans treat other non-human creatures. Do we consider the intelligence of a chicken, for example? It's inconvenient to do so, as it would suddenly thrust upon us ethical considerations to how we treat them. We (some) would rather just factory farm and eat them.

Perhaps because of our own limitations (culling less likely useful streams of thought) we tend to disregard things we don't understand. That does not mean they are lacking in value. It just means we have not made much effort to ascertain their capabilities.

Consider this perspective. If you were a stock investor, how would you value a modern Beethoven? You might try to determine the potential value of sales of his creations, but you would likely disregard the non-financial value of his music. Does that mean his music was not worth much?

vitaminbandit• 9 years ago

Don't romanticize what is a huge disability for a great many people. And you're not doing anyone any favors by mentioning the intelligence of chickens to make what you think is a point.

kmonad2• 9 years ago

I'm glad you are saying this. Today, especially on forums like here and perhaps reddit, autism is almost a badge as it is used frequently simultaneously with high intelligence. Yet, there really is not very clear evidence for this (there is some evidence that genetic patterns between highly intelligent and autistic individuals tend to overlap). I worry about this because it tends to render being autistic 'as not so bad', and downplay that autism is a disability.

safanycom• 9 years ago

I think it acts as a genetic counterbalance to ADHD. They gave the ability to blue sky a problem (ADHD) or a dictionary attack (ASD) or Fuzz a problem (Both together). Twice exceptional are attracted -- which carries on the gene pool.

bad_user2• 9 years ago

I think you have the wrong idea about how autism manifests itself.

In fact for many people suffering from autism, one of the symptoms is ADHD ;-)

gwern2• 9 years ago

This is an odd blog post. I'm not sure the authors really understand the genetics they are trying to invoke. For example, when they say:

Research has shown that some key autism genes are part of a shared ape heritage that predates the “split” that led us along a “human” path. This was when our ancient ape ancestors separated from other apes that are alive today. Other autism genes are more recent in evolutionary terms—though they are still more than 100,000 years old.

This is a really misleading use of 'autism gene'. All this means is that a particular 'gene', in the sense of a large chunk of DNA which codes for a protein and not the usual sense of a distinct variant/allele present in only part of the population, when damaged or modified leads to autism. (So you would take all the GWAS hits and note that the SNPs tend to cluster in particular gene-regions.) This might tell you something about what biochemical or developmental pathways lead to autism when broken, but it doesn't tell you anything like 'autism is good' or 'autism helps humanity evolve'. At best, it tells you that autism is sometimes connected to relatively recent biological changes, which is not a surprise (what would an autistic chimpanzee look like?). You could make the exact same argument about schizophrenia: 'genes' (in the sense of large genetic units) in which schizophrenia SNPs often turn up are also often relatively recently evolved or related to the nervous system. Did 'humanity need schizophrenia to evolve'? Seems unlikely. The parsimonious interpretation is that the human central nervous system and other things have been evolving over the past 200k+ years and diverging from the other primates, supporting modern human intelligence and cognition, and autism and schizophrenia are simply ways that our brains can break and the newly-evolved stuff can break often thanks both to the constant introduction of new mutations and demographic events like Neanderthal introgression. (Neanderthal variants typically are harmful and are being evolved away. That must have come as a shock to those people claiming Neanderthal contributions made you smarter or something.)

If you wanted to show that autism and genetic variants disposing to autism really does offer adaptive value or was important to the process, rather than simply reflecting the fragility of the human mind and long-standing mutation load, you would look for signs of selective sweeps for autism variants (either the rare variants of large effect or SNPs; none have been identified) or at least frequency-dependent selection (inconsistent with the additive genetic architecture), beneficial genetic correlations (there are none except some with intelligence), predicting any kind of better health (the opposite, indeed, just today: http://biorxiv.org/content/early/2017/06/09/148247 ); higher reproductive fitness in past or present populations (hah!) etc.

The other arguments like 'cave art', well... I'll leave that to others.

contingencies• 9 years ago

I'll defer on you to genetics, but I think you are unfairly dismissing the larger point raised, ie. that different societies have historically had different interpretations of, degrees of acceptance of and methods of utilizing the different qualities of autistic people, some potentially more enlightened than ourselves.

FWIW I found the reindeer herder story quite convincing. I have personally met and spoken to some fascinating people who could be ascribed a similar position, eg. a Himalayan Naxi hermit who endures near total isolation 9 months per year (his daughter and grand daughter took me with them on a rare visit, which was at the treeline a whole (predawn to nightfall) day's return walk above the nearest settlement). Approaching his position, we were overtaken by an animal skin clad mountain Yi vagabond who could double our pace at altitude. (My guides explained he would summit and descend the snow-capped mountain range for the safety of the next valley before nightfall.) A friend of mine from a young age is heavily autistic, to the point where only the extreme devotion of his father allowed him to begin to speak. He now runs a video store with his encyclopedic knowledge of film.

gwern2• 9 years ago

Whether historical societies were really all that tolerant is an interesting question, but the sense I get from OP is some extremely dubious misinterpretations of science and art in the service of pushing a pro-autism agenda.

dredmorbius• 9 years ago

Related, Darwin's exploration of emotion: https://en.m.wikipedia.org/wiki/The_Expression_of_the_Emotio...

Mz• 9 years ago

This article is crappy. The closing quote is attributed to someone whose name I don't know, but they probably got it from Temple Grandin.

All human evolution was driven by slightly autistic Asperger’s and autistic people. The human race would still be sitting around in caves chattering to each other if it were not for them.

She has a PhD and has designed something like half of all the cow processing plants in the U.S. (This is probably not the right name for them.) She is endlessly fascinating and if you have a child who is ASD (or if you have other reason to be interested) and you want some inspiration that isn't some sort of feel-good tripe, you should check out her works. There are a number of good books either by her or about her and she is a brilliant advocate for the autism community.

Her website:

http://www.templegrandin.com/

someSven• 9 years ago

The movie about her is also worth watching, IMHO. With Claire Danes.

boomboomsubban• 9 years ago

His quote comes from an interview about a 2006 book he published, Grandin loved the book and spoke highly of it around then, and then her quote comes from her 2008 book.

What role did autism play in human evolution?

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