What do you think causes Autism?

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There are many problems with retaining disadvantagous traits in a single lineage for 100,000 years. The most important being:
1. The traits would not be related if they were "throwbacks" to our own lineage
2. Time is the primary eliminator of disadvantagous traits, and I cannot see how differences in communication could survive for 100,000 years within a species.
3. I cannot even see how differences in communication could evolve at all. These traits should get extinct directly, more or less. Unless it was related to a known split between breading populations or introgression.

genes, genes and genes.

ruveyn

genes and certain marked sensitivities....

Before the mid twentieth century evolutionary synthesis there was a focus on how traits seem to often slide back and forth when specific environmental influences were in play. The focus on natural selection exclusively as what causes change, shifted the discussion, making it harder for the dynamics behind some forms of autism to be clear.

Neoteny is part of what is called heterochronic theory, or what I'm now calling it, orchestral theory, as it becomes more clear what specifically encourages shifts in traits that a whole group of people, exposed to the same social structure or environmental influences, could slide or shift at the same time.

The most obvious example is when you cross breed to breeds of a species that have not interbred in some time, and display different features. What happens is that often the progeny display features of the last common ancestor. We call this hybrid vigor. The "throwbacks" can bring forward both features useful and non useful to the present situation.

Changes in social structure also compels changes that cause these shifts to forebear features. Changes in testosterone and estrogen levels influence maturation rate and timing, adjusting ontogeny or growth, also influencing shifts to forebear features.

Mixing long separated lines, changes in social structure and environmental effects that influence maturation rates all can cause autism or Aspergers and a number of associated conditions. Darwin's other two theories, sexual selection and pangenesis were intensely focussed on these issues.

I am the AS-ish left-handed daughter of my AS-ish left-handed mom...But she was the only one in her family with noticeable traits...although she has said that her dad was very quiet and mathematical...and never really connected with anyone..and she thought that maybe he had PTSD from WWII.

There are also a lot of AS-ish/OCD traits on my dad's side of the family..but not everyone on that side of the family has had marked spectrum-related impairments...though some did...like my paternal grandfather's younger brother.
A lot of people from that side of the family are of above-average intelligence...even a sort of hyper-intelligence....lots of inventors, engineers and musicians...AND artists...

My NT (for all practical purposes) sister might possibly be "Borderline"....

And I, despite all my spectrum-related issues....and supposedly "above-average" intelligence was riddled with learning troubles...and my attention problems and executive dysfunction and social clumsiness have weighed me down substantially...so it seems like I have average-to slightly below-average intelligence.

I would also note that when I was younger, I seemed to develop somewhat normally to a degree...and then took some turns that changed me and I got a whole lot worse by the time I went to school....

Some of these turns might have been head injuries...and there was a time when I was extremely sick and bed-ridden...and everything sorta slipped into a dream for a long time...
I do know that my sensory issue were at their worst after the age of 5 or so.

I have spent too much time analyzing the fragments of memory that I have from when I was a child....

I would of thought it was in the genes or the vaccine that i was given because I was a NT for 2 weeks of my birth as it seems.
But I was dropped as a baby, maybe I would of still been a NT but it turned out i didn't live that way. Turns out i'm living the autistic life, the struggles and the challenges I had to go through, it was so hard but eventually i pulled through to go through this way.

My dad also has autism and he only had got diagnosed two years ago. So I would of thought it was genetic but the thing his parents knew about it but he didn't have a clue anything about it until two years ago, I would be feeling frustrated if I was him thinking why im like that?

In my opinon, i think it could be caused by a various things like being dropped, genetic, vaccaines that i have read on the news. I just think to myself I missed out on being a NT. Now I just think im glad im autistic because ive realise its harder to be a NT, but its hard either way.

re: Mothers with higher levels of testosterone, does it mean women who naturally have more testosterone or women who have higher levels during pregnancy because of another factor? I have the longer ring finger, I was a tomboy and while I'm not mannish, no one has ever called me a girly-girl.

Both mothers with naturally high levels of testosterone and mothers influenced by the environment whose testosterone levels are raised have increased chances of having an autistic child, according to the hypothesis.

I'm hypothesizing that raised mother's estrogen levels ALSO influence the likelihood of autism. This possibility has not appeared in the literature that I am aware of, though I exchanged some emails with Baron-Cohen about this and he thought the idea interesting.

The issue is, if at puberty a male and female can experience a delay in testosterone surges pruning cerebral synapse growth because estrogen levels are too low (not enough body fat), might the same thing be happening to infants with low estrogen levels, with the result being that the right cerebral hemisphere does not get pruned in the way that a normal right handed, neuro typical gets pruned.

In other words, do the autistic have big brains (20% are in the 95 percentile) because of low estrogen levels? And, are estrogen levels directly related to a mother's estrogen levels in the way that testosterone levels in children are directly related to testosterone levels in the mom?

And uber awsomeness

What kinds of environmental factors would raise testosterone levels?

The big question is the causative direction. Do mothers inherit higher testosterone levels by virtue of genes, or is this an environmental phenomen? Personally, I do not buy the skewed gender ratio in ASCs as a fact, but rather as a consequence of a male-defined diagnosis. About the only evidence that the "extreme maleness" theory has is the skewed gender-ratio. If this is only an articfact of diagnostic definition, this only evidence also disappears.

God (or whatever you call yours)

Eggman, I can't yet link to web pages (wrongplanet software allows me to link after 5 days of participation to prevent spam) but here are some examples...Eight environmental variables influence testosterone, including light (Geschwind & Galaburda, 1987), diet (Schmidt, Wijga, Von Zur Muhlen, Brabant & Wagner, 1997), body fat (Ross, Bernstein, Judd, Hanisch, Pike & Henderson, 1986; Glass, Swerdloff, Bray, Dahms & Atkinson, 1977), alcohol and drugs (Castilla-Garcia, Santolaria-Fernandez, Gonzalez-Reimers, Bastita-Lopez, Gonzalez-Garcia, Jorge-Hernandez & Hernandez-Nieto, 1987; Ahluwalia, Clark, Westney, Smith, James, & Rajguru, 1992), tobacco (MacMahon, Trichopoulos, Cole & Brown, 1982; Barrett-Connor & Khaw, 1987), touch, physical activity (MacConnie, Barkan, Lampman, Schork, & Beitins, 1986; Morville, Pesquies, Guezennec, Serrurier & Guignard, 1979) and stress (James, 1986). Estrogen has been far less studied, but diet has been repeatedly shown to dramatically influence estrogen levels (Ahluwalia, et al., 1981).

rdos, regarding causative direction both genetics and environment are in play. Social structure is integral to understanding both genetics and environment, but in relation to genetics, we tend to be predisposed to a particular social structure orientation. That influences a mother's testosterone levels. Matrifocal = high female testosterone. Patrifocal = low female testosterone.

I've read different studies with different male/female autism/Aspergers retios. One has Aspergers at 1/16 female/male. Exploring those studies in detail is not something I've done.

i am pretty sure before vaccines and crap there was autism. they just called it different things. if you were "Crazy" in old england, you were sent to the attic. in other cultures you would be considered a shaman. this goes for schizophrenics, too. if you are epileptic in vietnam area and are a member of the hmong, your soul would have been considered taken away by neighboring spirits. these concepts fall under the umbrella term "ethnomedicine." just because they called it different things, they could still be autistic. another example: homosexuality. fifty years ago homosexuality was a mental illness. but, if you happened to be hindu, they had a special sub-genre for you. it was considered ok. you got to be a "priestess" if you were male. many shamanistic societies see the "dual spirit" of homo- and bi-sexuals as being holy and of two worlds. you would have been revered, most likely. luckily there are many different kinds of shamans, so there isn't just one type. anyone "different" could apply, more or less, within the context of the said culture, of which there are many.

so, in essence, i think all of this vaccine crap is balderdash. of course, it could affect the brain of a developing baby. i haven't done much research myself, so it could very well be. it seems as rampant as the "bloody mary" thing in fifth grade, or whatever urban legend is popular now-a-days. of course, with more research being done, who knows? like, if you live on a place that has a lot of heavy metals, you are more likely to get a development health problem than not at all, i guess. (i live in buffalo. there is a LOT of hypothyroids here. hmm?)

there is my 2cents as an anthropologist in training.

Yes, I agree, and this is a huge problem with DSM. They are mixing up inherited behaviors, odd personality traits and results of bullying and social exclusion into a mess. There is no way to find a single cause for all of this in the present form.



I didn't know that, but it makes a lot of sense. Especially the tendencies of Aspie males to be more traditionally feminine and of Aspie females to be tomboys.



I've researched this myself, and there is a tiny overweight of diagnosed males that do Aspie-quiz, but at the same time females score considerably higher on Aspie-quiz. Factors and explained variances are practically identical regardless of age and gender, and scoring is based on factor-loadings. Therefore, I do not think there is any gender bias for the broader autism phenotype.

In the evolution section of shiftjournal dot com I've posted several short pieces revolving around these issues of male/female incidence rates and the impact of hormones and social structure on causes. It's blog format easy to post comments. Folks with Aspergers/autism are posting articles there if anyone wants to do so.

I'm really enjoying this thread focusing on evolutionary causes, and other causes. Are there are places folks here would recommend I travel to for these kinds of sharings?