Fitting predictions from evolutionary psychology perspective exactly

To me, this is a very strange assertion, because evolutionary psychology is sort of notorious within my scientific community for being more than slightly fond of post-hoc reasoning: that is, starting with the conclusions and fitting the predictions to them. So that being said, Mr. Damore’s assertion here feels incredibly tautological to me.

Let me explain a little more about my own personal training and the ways that scientists in my field, which is again broadly the evolution of animal behavior, tend to feel about evolutionary psychology. And let’s talk for a minute about how the intersection of the study of behavior and the study of evolution and genetics has developed over time, and the reason that it’s a little difficult for me to give a one-word summary of what kind of biologist I am, as opposed to Mr. Damore’s label of “systems biologist.”

It’s important first to point out that the intersection of evolution and behavior is studied by a number of disciplines and traditions, not only evolutionary psychology. In addition to my own field of behavioral ecology, these topics are often touched on by population geneticists, behavior geneticists, anthropologists (in fact, this is where where anthropology originated), animal cognition specialists, and so on and so forth. (I’m not even naming older disciplinary names like sociobiologists and ethologists that I rarely see in use today.)

All of these names refer to distinct traditions of work⁴⁹ which usually have historical frames in which a topic is approached and discussed, with varying levels of cross-talk among them, sort of like a long ongoing conversation. For example, behavioral ecology largely derives from the study of animal behavior in a naturalistic context first pioneered by Niko Tinbergen and Konrad Lorenz,⁵⁰ whereas animal cognition — also focusing on the study of animal behavior — tends to owe more to studies of cognitive biology that attempt to compare cognitive capabilities between species with an eye towards using them as models to understand human cognition. Evolutionary psychology itself is a distinct tradition of work with its own history and major players, largely rising out of a vogue for applying sociobiology ideas to humans.⁵¹

It’s why my home department is “integrative biology” rather than its old name, which was “zoology”. As techniques in molecular biology have become more accessible and more cost effective, biologists have branched out into different techniques and increased standards of evidence. That means that someone like me, whose theoretical background has a very strong foundation in evolutionary biology, might pick up techniques from neuroscientists, molecular biologists, geneticists, and cell biologists to delve into the mechanisms that lie under the topic I’m interested in. There’s overlap, but the names we choose for ourselves say something about the way we approach our topics of research.

Many of us read widely in multiple traditions, and it’s common in my department for students to cross-train with at least one course hosted by another department. My own lab contains students who work on brain immunohistochemistry, field biology, geotracking, pure behavioral work, epigenetics, and so on and so forth. In order to properly understand behavior, it helps to be able to approach it from multiple angles and multiple points and frames of view. This spirit of cross-disciplinary work is generally reflected throughout the department; I often see and work with students from the cell and molecular biology and neuroscience departments at my university in particular, and I have worked alongside, taken classes with, or discussed seminars alongside plenty of palaeontology students (from the geology department) and psychology students from a number of subdisciplines.

Curiously, however, these disciplines do not include evolutionary psychologists: I have never met an evolutionary psychology student taking any course, presenting at any evolutionary biology seminar, or interacting in any way with the evolutionary biology students in my own department, and I have never seen a behavior-focused Ecology, Evolution and Behavior student from my own department mention spending time learning from evolutionary psychologists. This is particularly odd because my university, which is the University of Texas at Austin, happens to host an extremely prominent evolutionary psychologist in the form of Dr. David Buss…and also several prominent and well respected behavioral ecologists in my department, most of whom are specifically prominent in the field of sexual selection and courtship behavior itself. This is also a topic that evolutionary psychologists have a well documented and particularly strong interest in, and this includes Dr. Buss. So why the lack of collaboration?

The answer boils down to the fact that evolutionary biologists and behavioral ecologists — which is, again, the term usually used to describe people studying the evolution of animal behavior in a naturalistic context — are typically some of the most vocal critics of evolutionary psychology.⁵⁰ ⁵² Indeed, several prominent behavioral ecologists have written popular science books that criticize evolutionary psychology openly.⁵³ ⁵⁴

Why might this be the case?

One huge issue is the question of adaptationist hypotheses. Evolutionary biology had a large intradisciplinary discussion back in the late 1970s and early 1980s about adaptationist thinking, largely kicked off by Stephen J. Gould and Richard Lewontin’s classic paper The Spandrels of San Marcos. The central argument of this paper is that evolutionary biologists should not assume that the null expectation for any observable biological trait is that the trait is in some way an adaptation for survival. Indeed, some traits arise as accidents of pleiotropy — genes with multiple effects — and some merely develop over time by chance. Gould and Lewontin argued that in order to describe a trait as a known evolutionary adaptation, evolutionary biologists first needed to identify some evidence that the trait was both adaptive to survival and also that it had sufficient heritability for selection to be capable of acting on it.⁵⁵

While this paper was controversial at the time it was published, it has largely become accepted among evolutionary biologists that it is generally correct. In fact, I have most often seen evolutionary biologists use the term ‘adaptationist thinking’ amongst themselves as a slur, implying that another scientist’s research paradigm is insufficiently critically rigorous; it’s a term right up there with ‘telling Just-So stories’ within the field. It doesn’t mean that you can’t hypothesize that a trait evolved because of positive selection — it just means that adaptationist hypotheses must be tested against a null, neutral hypothesis.

By contrast, evolutionary psychologists openly argue that adaptationist assumptions are essential to the field and are simply good science, and that starting with adaptationist hypotheses just makes sense.⁵⁶ This is further confounded by the methodology generally chosen in the field of evolutionary psychology (see below), which is typically limited to surveys confirming that the behavior in question does in fact exist — something even acknowledged by defenders of the field’s capabilities of falsification.⁵⁷ Occasionally fMRI studies are also used.

Unfortunately, these techniques do not directly confirm the underlying reasons or development of the behavior at hand, and so their use is often viewed as dubious by evolutionary biologists and neuroscientists⁵⁸ used to being able to rely on heritability, candidate genes which can be tested for genetic markers of selection, or between-species phylogenetic analyses in order to make inferences about evolution. In part, this is because it is difficult to use many of the methods available to a behavioral ecologist on humans for reasons of ethics and, often, feasibility.

For example, a popular technique to understand changes in the brain for behavioral ecologists is the immediate early gene study, which attempts to understand changes in gene regulation that happen as a response to a behavioral stimulus. In this technique, animals are exposed to one of two stimuli, given a set period of time for changes in genetic regulation to take place (typically on the order of 60 minutes) and then sacrificed. Brains are then sliced and stained for the proteins produced by so-called “house-keeping genes” which are known to herald large-scale changes in genetic regulation in the brain; large amounts of housekeeping proteins like egr-1 or c-fos imply that brains are responding to stimuli by reconfiguring their signaling systems in these places.⁵⁹

Once this has been done, further studies may compare gene expression differences between individuals in different treatments in the brain regions indicated by the immediate early gene study, which can then be studied for evidence of evolutionary changes. It does not take a large stretch of the imagination to understand why this is not a mechanistic technique available to the enterprising evolutionary psychologist. However, because evolutionary psychologists are frequently hampered by any ability to assay mechanisms of change or find genetic evidence of selection (or even hard evidence that traits are genetic), evolutionary biologists frequently criticize evolutionary psychology as proceeding post-hoc by observing behavioral variation without adequately determining causative mechanism and inventing potentially adaptive explanations for these behaviors. This is unacceptable methodology by the standards of any behavioral ecologist.

Evolutionary biologists and behavioral ecologists sometimes also raise eyebrows at the contention held by nearly all evolutionary psychologists that humans have not had time to evolve appreciably through the brain since the Paleocene.⁴⁴ ⁵³ In fact, evolutionary biologists know that evolution can happen quite quickly, and indeed have demonstrated several cases of human evolutionary adaptation since the advent of agriculture.⁶⁰ This is particularly true since behavioral change is likely to be mediated by selective changes in gene regulation rather than in coding regions themselves.⁶¹

(A quick note on fMRI, because not many people are particularly familiar with how to read fMRI studies. If you’ve ever seen a study that presents pictures of glowy heat maps superimposed on a human brain, that is an fMRI study. While fMRI studies are often described as “measuring brain activity,” what is actually being measured is the flow of blood to particular regions of the brain by measuring very subtle changes in the magnetic fields within the device. The implicit assumption is that brain regions which are requiring more blood flow are doing something different, but this is a much vaguer kind of statement to make than can be made after an immediate early gene study or a direct measurement of neuronal firing ability, also a technique used by behavioral ecologists. fMRI studies are also much more vulnerable to false positive errors in testing because each voxel of the brain is continuously being tested for changes in blood flow throughout the experiment, and with such a large sample size seemingly meaningful patterns can emerge by chance alone. In fact, a very well publicized incident in which a dead salmon was placed into an fMRI scanner and showed significant activity galvanized the fMRI community and resulted in better use of multiple comparisons correcting several years ago.⁶² ⁶³)

So in conclusion, it seems to me to be quite funny to argue that your concepts of human biological gender differences are correct because they fit all the predictions of evolutionary psychology, when evolutionary psychology is a discipline that notoriously fails to study the actual evolution part of the behaviors it discusses, instead using certain aspects of evolutionary theory to generate hypotheses. Evolutionary psychology’s predictions are post-hoc and derive from assuming the existence of “biological” differences between sexes to start with.