7 ms·

What role did autism play in human evolution?

31 points by sajid 9y ago

nv-vn 9y 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.
- dwringer 9y 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 9y 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.
    - dwringer 9y ago
      Thanks, I actually do understand what you mean but then I simply must refer you to the rest of what I quoted. There is no distinction, it simply comes down to a diagnosis based on a number of factors - otherwise we are "all a bit autistic". Since that diagnosis is a relatively recent invention, it's hard to understand your argument about "autistic people" historically.
- deleted 9y ago
  [deleted]
- samhain 9y 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-vn 9y 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 9y 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 9y 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?
  - qb45 9y 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-illness/ http://www.jaysongaddis.com/the-shamanic-view-of-mental-illn...
  - sdiupIGPWEfh 9y 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.
TomasEkeli 9y 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.
- poizan42 9y 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 9y 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.
    - wbl 9y ago
      I had an IEP because of autism and work in the industry.
    - briholt 9y ago
      I think this is the DSM's criteria for high functioning autism.
      - poizan42 9y ago
        Having difficulty getting back on track after an interruption is part of ADHD (well, more difficulty than the average person, interruptions disrupts everybody's concentration to some degree). There is a high level of comorbidity between Autism Spectrum Disorders and ADHD-PI (formerly known as ADD).
safanycom 9y 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_user 9y 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 ;-)
gwern 9y 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 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.
dredmorbius 9y ago
Related, Darwin's exploration of emotion: https://en.m.wikipedia.org/wiki/The_Expression_of_the_Emotions_in_Man_and_Animals https://en.m.wikipedia.org/wiki/The_Expression_of_the_Emotio...
Mz 9y 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/ http://www.templegrandin.com/
- someSven 9y ago
  The movie about her is also worth watching, IMHO. With Claire Danes.
- boomboomsubban 9y 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.
rustynails77 9y ago
I am the parent of an Asperger. Like many other parents in similar situations, I have dealt with many autistic kids (low and high functioning). I get quite annoyed at the playing of the victim card just because somebody is autistic. It only serves to make things worse for everybody. When my child behaves unusually, the results from other children are negative. This would happen irrespective if my child was autistic or not. I used these negative opportunities to discuss standing out and blending in. There are times where it is not possible to blend in (ie. because of highly keen senses causing a crippling effect). However, that can be offset by playing to strengths. My autistic child has gone from strength to strength. When other parents have asked me what I did, I say I never told my child they were a victim and tried to steer them to blend in. While I can't definitely prove that is the only criteria, i've had many other parents comment on how my child's growth has stood out from other autistic children we deal with, despite starting in a similar situation. Don't get me wrong, it's not easy to separate what's essential (eg. separation from a noisy environment) from what sounds beneficial but wouldn't help (eg. I had to fight hard against using coloured cards instead of plain language to communicate). I am averse to gimmicks that make children stand out. These gimmicks can easily backfire and cause social alienation (i've seen a lot of it, first hand). One thing that Aspergers often have as an advantage is an obsessive nature. They want to know everything about a particular topic. They study, analyse, and study further. It's amazing to watch. I can imagine that this obsession can lead to some amazing breakthroughs. On this basis, I would say that it is possible that Aspergers can achieve exceptional results that others are less likely to achieve. This theory of mine aligns with others [0]. I actually found this link after watching the movie about Srinivasa Ramanujan, the genius Indian mathematician who struck me as having asperger-like characteristics. I am not fond of victim mentality articles. I'm not fond of turning people into victims. If you are a parent of an autistic child, please do your best to help them understand how they are different without creating a victim. Help them steer toward socially acceptable behaviour and to recognise their strengths. Everybody is different. Even the atypicals. Disclaimer: I'm married to an Asperger who became an engineer on her own steam. Despite being an engineer (a no bullshit engineer with no sense of entitlement or victim mentality), she's not had an issue with discrimination in her decades long career. How do some people make it through with no issues? That's an excellent question. [0] https://www.nature.com/nature/journal/v428/n6982/full/428470a.html https://www.nature.com/nature/journal/v428/n6982/full/428470...

31 points by sajid 9y 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.

dwringer 9y 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 9y 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.
  - dwringer 9y ago
    Thanks, I actually do understand what you mean but then I simply must refer you to the rest of what I quoted. There is no distinction, it simply comes down to a diagnosis based on a number of factors - otherwise we are "all a bit autistic". Since that diagnosis is a relatively recent invention, it's hard to understand your argument about "autistic people" historically.
deleted 9y ago
[deleted]
samhain 9y 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-vn 9y 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 9y 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 9y 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?
- qb45 9y 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-illness/ http://www.jaysongaddis.com/the-shamanic-view-of-mental-illn...
- sdiupIGPWEfh 9y 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.

TomasEkeli 9y 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.

poizan42 9y 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 9y 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.
  - wbl 9y ago
    I had an IEP because of autism and work in the industry.
  - briholt 9y ago
    I think this is the DSM's criteria for high functioning autism.
    - poizan42 9y ago
      Having difficulty getting back on track after an interruption is part of ADHD (well, more difficulty than the average person, interruptions disrupts everybody's concentration to some degree). There is a high level of comorbidity between Autism Spectrum Disorders and ADHD-PI (formerly known as ADD).

safanycom 9y 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_user 9y 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 ;-)

gwern 9y 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 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.

dredmorbius 9y ago

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

Mz 9y 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/ http://www.templegrandin.com/

someSven 9y ago
The movie about her is also worth watching, IMHO. With Claire Danes.
boomboomsubban 9y 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.

rustynails77 9y ago

I am the parent of an Asperger. Like many other parents in similar situations, I have dealt with many autistic kids (low and high functioning). I get quite annoyed at the playing of the victim card just because somebody is autistic. It only serves to make things worse for everybody. When my child behaves unusually, the results from other children are negative. This would happen irrespective if my child was autistic or not. I used these negative opportunities to discuss standing out and blending in. There are times where it is not possible to blend in (ie. because of highly keen senses causing a crippling effect). However, that can be offset by playing to strengths. My autistic child has gone from strength to strength. When other parents have asked me what I did, I say I never told my child they were a victim and tried to steer them to blend in. While I can't definitely prove that is the only criteria, i've had many other parents comment on how my child's growth has stood out from other autistic children we deal with, despite starting in a similar situation. Don't get me wrong, it's not easy to separate what's essential (eg. separation from a noisy environment) from what sounds beneficial but wouldn't help (eg. I had to fight hard against using coloured cards instead of plain language to communicate). I am averse to gimmicks that make children stand out. These gimmicks can easily backfire and cause social alienation (i've seen a lot of it, first hand). One thing that Aspergers often have as an advantage is an obsessive nature. They want to know everything about a particular topic. They study, analyse, and study further. It's amazing to watch. I can imagine that this obsession can lead to some amazing breakthroughs. On this basis, I would say that it is possible that Aspergers can achieve exceptional results that others are less likely to achieve. This theory of mine aligns with others [0]. I actually found this link after watching the movie about Srinivasa Ramanujan, the genius Indian mathematician who struck me as having asperger-like characteristics. I am not fond of victim mentality articles. I'm not fond of turning people into victims. If you are a parent of an autistic child, please do your best to help them understand how they are different without creating a victim. Help them steer toward socially acceptable behaviour and to recognise their strengths. Everybody is different. Even the atypicals. Disclaimer: I'm married to an Asperger who became an engineer on her own steam. Despite being an engineer (a no bullshit engineer with no sense of entitlement or victim mentality), she's not had an issue with discrimination in her decades long career. How do some people make it through with no issues? That's an excellent question. [0] https://www.nature.com/nature/journal/v428/n6982/full/428470a.html https://www.nature.com/nature/journal/v428/n6982/full/428470...