Seth’s blog

An interesting Economist article about sex differences in a visual task calls an evolutionary explanation a “just-so story.” I don’t know if the late Stephen Jay Gould, evolutionary theorist, Harvard professor, and “one of the most influential and widely-read writers of popular science of his generation” (Wikipedia), invented this form of dismissal, but certainly he was fond of it. Here, for example:

Evolutionary biology has been severely hampered by a speculative style of argument that . . . tries to construct historical or adaptive explanations for why this bone looked like that or why this creature lived here. These speculations have been charitably called “scenarios”; they are often more contemptuously, and rightly, labeled “stories” (or “just-so stories” if they rely on the fallacious assumption that everything exists for a purpose). Scientists know that these tales are stories; unfortunately, they are presented in the professional literature where they are taken too seriously and literally.

Well, this is seriously wrong. My work contains several just-so stories — evolutionary explanations of the morning-faces effect and of the mechanism behind the Shangri-La Diet, for example. My theory of human evolution might be called a just-so saga.

These explanations made me (at least) believe more strongly in the result or theory they explained — which turned out to be a good thing. My morning-faces result was at first exceedingly implausible. The evolutionary explanation encouraged me to study it more. After repeating it hundreds of times I no longer need the evolutionary explanation to believe it but the explanation may help convince others to take it seriously. The evolutionary explanation connected with the Shangri-La Diet had the same effect. My evolutionary explanation of the effect of breakfast on sleep led me to do the experiment that discovered the morning-faces effect. My theory of human evolution led me to try new ways of teaching, with good results.

Why did Gould make this mistake? Thorstein Veblen wrote about our fondness for “invidious comparisons.” We like to say our X is better than someone else’s X. Sure, evolutionary explanations may be hard to test. That doesn’t mean they’re worthless. Like many scientists, Gould failed to grasp that something is better than nothing.

Addendum: Perhaps the Economist writer had read a recent Bad Science column that began:

I want you to know that I love evolutionary psychologists, because the ideas, like “girls prefer pink because they need to be better at hunting berries” are so much fun. Sure there are problems, like, we don’t know a lot about life in the pleistocene period through which humans evolved; their claims sound a bit like “just so” stories, relying on their own internal, circular logic; the existing evidence for genetic influence on behaviour, emotion, and cognition, is coarse; they only pick the behaviours which they think they can explain while leaving the rest; and they get themselves in massive trouble as soon as they go beyond examining broad categories of human behaviors across societies and cultures, becoming crassly ethnocentric.

“They only pick the behaviours which they think they can explain” — how dare they!