Just-So Stories

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.