A recent paper on the evolutionary psychology of reasoning has made mainstream news, with extensive coverage by the New York Times, among others. Too bad the “research” is badly flawed, and the lesson drawn by Patricia Cohen’s commentary in the Times is precisely the wrong one.
Readers of this blog and listeners to our podcast know very well that I tend to be pretty skeptical of evolutionary psychology in general. The reason isn’t because there is anything inherently wrong about thinking that (some) human behavioral traits evolved in response to natural selection. That’s just an uncontroversial consequence of standard evolutionary theory. The devil, rather, is in the details: it is next to impossible to test specific evopsych hypotheses because the crucial data are often missing. The fossil record hardly helps (if we are talking about behavior), there are precious few closely related species for comparison (and they are not at all that closely related), and the current ecological-social environment is very different from the “ERE,” the Evolutionarily Relevant Environment (which means that measuring selection on a given trait in today’s humans is pretty much irrelevant).
That said, I was curious about Hugo Mercier and Dan Sperber’s paper, “Why do humans reason? Arguments for an argumentative theory,” published in Behavioral and Brain Sciences (volume 34, pp. 57-111, 2011), which is accompanied by an extensive peer commentary. My curiosity was piqued in particular because of the Times’ headline from the June 14 article: “Reason Seen More as Weapon Than Path to Truth.” Oh crap, I thought.
Mercier and Sperber’s basic argument is that reason did not evolve to allow us to seek truth, but rather to win arguments with our fellow human beings. We are natural lawyers, not natural philosophers. This, according to them, explains why people are so bad at reasoning, for instance why we tend to fall for basic mistakes such as the well known confirmation bias — a tendency to seek evidence in favor of one’s position and discount contrary evidence that is well on display in politics and pseudoscience. (One could immediately raise the obvious “so what?” objection to all of this: language possibly evolved to coordinate hunting and gossip about your neighbor. That doesn’t mean we can’t take writing and speaking courses and dramatically improve on our given endowment, natural selection be damned.)
The first substantive thing to notice about the paper is that there isn’t a single new datum to back up the central hypothesis. It is one (long) argument in which the authors review well known cognitive science literature and simply apply evopsych speculation to it. If that’s the way to get into the New York Times, I better increase my speculation quotient.