The DCIDE Framework published in Biological Reviews by Adam Hunt and Adrian Jaeggi.
Since the first night I stumbled upon evolutionary psychiatry, with a background in philosophy of science, I saw a major problem: how can you prove or decide between any of the (many) evolutionary hypotheses of a particular disorder?
Yes, exactly. The just-so stories abound in psychology, especially evo psych. "Mania developed because in times of emergency a) being able to stay awake for hours was adaptive, b) the added charisma of hypomania is useful for leadership, c) overconfidence works sometimes, d) all of the above, plus six others." We like stories. They help us understand and remember important ideas. Yet sometimes they are entertaining but wrong.
Hunt and Jaeggi have designed a standard for evaluating the explanations, then they try it out on a recognised condition that has fuzzy edges, definitional problems, and unclear etiology, in this case autism (which is how I got interested). So they are not going for the low-hanging fruit here, they are trying to figure out a difficult and contentious issue.
Basically, the systemising niche hypothesis states that autistic traits are ‘specialised minds’ (see mine and @ajaeggi other paper). Cognitive strengths and weaknesses balance out, with autistic traits advantageous in a proportion of the population because of their benefits to systemising, but don’t spread universally because they have costs.
The by-product hypothesis, on the other hand, points to intelligence in the whole human species as the advantage: autistic traits are harmful overshoots which are exaggerated versions of ‘perceptual’ intelligence. This doesn’t imply autistic traits were somehow selected for strength/weakness profiles.
2 comments:
Hey, I just finished reading the book Blueprint! The author's thesis is, most "disorders" like schizophrenia, mania, autism, or (in his case) gigantism aren't really things you either have or you don't, they're just people at one tail of the bell curve for traits that everyone has to some extent. Further, they're all influenced by a large number of genes, none of which have a strong effect on an individual trait, and all of which affect many other traits.
There's this weird idea that selection has to somehow act on the level of traits, but I don't know where it comes from. A gene variant will become more common if it tends to increase fitness overall, directly or indirectly.
I would concur. Most extreme conditions, like gigantism or autism, have versions which are single gene, de novo mutations. But these only account for 5-20% of the total. The rest are, as you say, outliers based on gene stacking.
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