Zombie Psychology: Bad Ideas That Simply Refuse to Die
At the risk of reopening a can of worms, Jerry Coyne’s recent post I think helps clarify why he dislikes the field of evolutionary psychology so much.
Coyne is responding to someone he refers to as a “lurker” on his blog who asked him to give an example of a an evolutionary psychology study he (Coyne) thought was good. I of course applaud Coyne for taking the time to do this. I think that it’s a very useful way to try to move forward.
What can we learn about Coyne’s choice of a “good” paper in evolutionary psychology? It is a paper published in The New England Journal of Medicine in 2004 by two medical doctors, William Reiner and John Gearhart. Briefly, the paper reports an investigation of genetically XY babies with a particular disorder that affects the genitals. The babies are surgically made female and raised as female. This study (N=16) asked the question of whether these individuals – genetically male but raised as females, with vaginas rather than penises – identified as males or females when they got older. Briefly, many of the subjects self-identified as males.
One could quibble about the identification of a study with a small N, in which double blinding is impossible, and so on, but I think that would miss the point, except insofar as it illustrates that Coyne doesn’t object to studies on these grounds per se, but simply applies these criticisms when he dislikes research for some other reason.
The important point is that I think that there is a lot of information in this choice. Obviously, it’s interesting that he doesn’t select a study conducted by people who self-identify as evolutionary psychologists, or is published in an evolutionary psychology journal. He passes over Joe Henrich’s award-winning work, to take just one example.
My sense is that he sees this work as distinguishing whether gender identity is “biological/genetic” as opposed to “cultural/learned.” You can see Coyne’s views on this when he writes: “The results show that, to a large extent, the roots of gender-specific behavior are biologically rather than socially based, and are present at birth,” drawing the biology/culture distinction, which evolutionary psychologists explicitly reject. (See below.) (Coyne mentions that he got into this work because Pinker referred to it in The Blank Slate. Pinker concludes from this and related work that the hypothesis that “boys and girls are born identical except for their genitalia” is “not looking good,” a claim about the origin of variation between the sexes.)
From his choice, then, one might infer that Coyne thinks evolutionary psychology is about showing that traits are “genetic” or “innate” as opposed to “learned,” a very common misconception among people unfamiliar with the field.
Another way to see why he objects to the field is his view of ultimate explanations in evolutionary psychology. He writes that what he likes about this particular study in JAMA is that is “comprises a simple test of a simple hypothesis, and does not involve telling tortuous adaptive “stories” to rationalize the results.” I don’t know what he means by “rationalize” there (let alone “tortuous”), but I take it from this that he thinks explanations in the case of humans are preferable if they include only a proximate explanation as opposed to a proximate and ultimate explanation.
So it seems to me that this choice is very helpful in illustrating the origin of his irritation with the field. He thinks, I infer, that the agenda of evolutionary psychology is to claim that human behavior is innate, fixed, genetic and biological rather than learned, flexible, and cultural. A sensible person who thought this, and observed human variation, would quite reasonably conclude that there are problems with the field. Of course, this gets the commitments of the field wrong, which is why these conversations recur with regularity. Similarly, it’s true that the field commits to the value of both proximate and ultimate explanations, just as evolutionary biology does. Of course if he thinks that ultimate explanations are a liability rather than an asset, he finds the field that much worse.
Future conversations will be limited in their usefulness until we can at least agree on what it is that we disagree about. While (many) evolutionary psychologists think the productive axis of debate is the specificity of cognitive mechanisms, interlocutors such as Coyne still seem to want to have the debate about nature versus nurture. True, that’s not the only issue. There remains the question of why he thinks that an adaptationist analysis and ultimate explanations are useful for seahorses but unwanted “stories” for humans, but my sense is that the first order of business is to agree about the axis of debate.
And, maybe just for completeness, here is a passage on this issue from Cosmides and Tooby in their online primer:
Debates about the “relative contribution” during development of “nature” and “nurture” have been among the most contentious in psychology. The premises that underlie these debates are flawed, yet they are so deeply entrenched that many people have difficulty seeing that there are other ways to think about these issues.
Evolutionary psychology is not just another swing of the nature/nurture pendulum. A defining characteristic of the field is the explicit rejection of the usual nature/nurture dichotomies — instinct vs. reasoning, innate vs. learned, biological vs. cultural. What effect the environment will have on an organism depends critically on the details of its evolved cognitive architecture. For this reason, coherent “environmentalist” theories of human behavior all make “nativist” claims about the exact form of our evolved psychological mechanisms. For an EP, the real scientific issues concern the design, nature, and number of these evolved mechanisms, not “biology versus culture” or other malformed oppositions.