[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]

Some in the scientific community are criticizing the so-called “post-hoc” claims of evolutionary psychology. This is the discipline that explains modern behavior using theories of human adaptation over thousands of years.

But a paper in press by Lisa DeBruine at the University of Aberdeen defends evo psych by offering another angle. She writes: “…the real power of an evolutionary perspective lies not in generating…reasons for behavior that we already know about, but in generating novel predictions about behaviors that have not yet been investigated.”



DeBruine points to an evolutionary way of thinking that can allow us to ask new questions that then lead to testable hypotheses. Take this example: back in the mid-60s predictions were made about how humans perceived vertical and horizontal distances differently.

One such theory predicted that vertical distances are overestimated when viewed from bottom up. But no experiments were done, until researchers proposed a possible evolutionary reason for the discrepancy in vertical views.

And here the researchers predicted that humans ought to overestimate a vertical distance from top down, versus looking up from below because of this evolutionary reasoning: a fall from a high perch is much more likely to lead to death or injury. And this ain’t good for the overall fitness of the species.

Russell Jackson and Lawrence Cormack confirmed this effect in 2007. They found that nearly all of their 210 subjects (from two separate experiments) perceived the height to be 32 percent greater when looking down than when looking up.

DeBruine’s point in her paper is that evo psych perspectives are valuable not because they provide reasons for human behavior, but because they lead to new hypotheses that then lead to discovery that is supported by verifiable evidence.

—Christie Nicholson