Journal sam_handelman's Journal: Autism and human evolution 5
Heh. I got a 14.
Firstly, autism is not a real trait. It is a classification we use when discussing a family of (probably completely unrelated) traits with similar outcomes in terms of making people behave like Rainman. Even Asperger Syndrome is classified exclusively on the basis of behavior - if there is a syndrome there, we don't have a fraction of the depth of understanding needed to know what it is.
Now, you can still make an argument that this class of autistic traits has been, or will be, selected for in the human population. In both cases, we can only speculate.
I maintain that human beings have been selected for intellectual diversity. A tribe of humans would survive best if it had some members who were cautious, some who were bold, some who were more capable of abstract thought, some who were more sociable, and so forth. In some cases there is a tradeoff, due to the engineering limitations of the human nervous system.
It is also possible - as is the case with Cystic Fibrosis, for example - that there are genes associated with autistic traits that have some beneficial effect when present in single copy. This is total speculation, however - our understanding of the relationship between human genetics and human intellectual diversity is shallow, at best. It is entirely possible that the spectrum of autism-like disorders are very rarely caused by genetics and mostly by environmental factors - the fact that they show some indications of heritability not withstanding (see child rearing practices below).
At present, the majority of selective pressure on human beings is cultural. Will we wipe ourselves out as a species? That's a big one, not a genetic question.
For individual humans, the question is becoming not "am I fit to reproduce?", or "am I rich enough to reproduce?", but "do I *want* to reproduce?"
The obvious effect of the wide availability of birth control is that people who just want to have sex without having children are now absolutely free to do so, and they will. This may have some impact on the frequency of genes that impact, for example, the strength of parent-child bonding one way or the other.
However, the overwhelming effect is going to be on child-rearing practices. If you have child-rearing practices that give you children who do not, in turn, want to have children - those child-rearing practices will die out. This is another form of cultural selection.
Of course, evolution is a slow process (Score:1)
People from 10,000 years ago are pretty much the same as now genetically, but our environmental and other conditions have changed.
Some exceptions exist among certain populations - for example, descendents of Africans who were transported aboard slave ships to America tend to have a higher incidence of certain disease probabilities because there was a very high death rate (sometimes up to 90 percent) of t
Some problems with this synopsis (Score:2)
This is total speculation, however - our understanding of the relationship between human genetics and human intellectual diversity is shallow, at best. It is entirely possible that the spectrum of autism-like disorders are very rarely caused by genetics and mostly by environmental factors - the fact that they show some indications of heritability not withstanding (see ch
2nd reply, I missed one (Score:2)
Firstly, autism is not a real trait. It is a classification we use when discussing a family of (probably completely unrelated) traits with similar outcomes in terms of making people behave like Rainman.
Rainman is widely considered among autistics to be a really bad, really stereotyped, potrayal of extremely low funcitoning autism. Rain
Dynamics Of Humanities (Score:1)
Heh. I got a 14.
By the way, what's this?
Firstly, autism is not a real trait. It is a classification we use when discussing a family of (probably completely unrelated) traits with similar outcomes in terms of making people behave like Rainman. Even Asperger Syndrome is classified exclusively on the basis of behavior - if there is a syndrome there, we don't have a fraction of the depth of understanding needed to know what it is.
Interesting. I myself used to have a misund
Re:Dynamics Of Humanities (Score:2)