Evolutionary Psychology: Tying Psychology Together

Every now and again – perhaps more frequently than many would prefer – someone who apparently fails to understand one or more aspects of the evolutionary perspective in psychology goes on to make rather public proclamations about what it is and what it can and cannot do for us. Notable instances are not particularly difficult to find. The most recent of these to cross my desk comes from Gregg Henriques, which takes a substantially less-nasty tone than I have come to expect. In it, he claims that evolutionary psychology does not provide us with a viable metatheory for understanding psychology, and he bases his argument on three main points: (1) evolutionary psychology is overly committed to the domain-specificity concept, (2) that the theory fails to have the correct map of complexity, and (3) it hasn’t done much for people in a clinical setting. In the course of making these arguments, I feel he stumbles badly on several points, so I’d like to take a little time to point out these errors. Thankfully, given the relative consistency of these errors, doing so is becoming more a routine than anything else.

So feel free to change the channel if you’ve seen this before.

Gregg begins with the natural starting point for many people in criticizing EP: while we have been focusing on how organisms solve specific adaptive problems, there might be more general adaptive problems out there. As Gregg put it:

The EP founders also overlooked the fact that there really is a domain general behavioral problem, which can be characterized as the problem of behavioral investment

There are a number of things to say about such a suggestion. Thankfully, I have said them before, so this is a relatively easy task. To start off, these ostensibly domain-general problems are, in fact, not all that general. To use a simple example, consider one raised by Gregg in his discussion of behavioral investment theory: organisms need to solve the problem of obtaining more energy than they spend to keep on doing things like being alive and mating. That seems like an awfully general problem, but, stated in such manner, the means by which that general problem is, or can be, solved are massively unspecified. How does an organism calculate its current caloric state? How does an organism decide which things to eat to obtain energy? How does an organism decide when to stop foraging for food in one area and pursue a new one? How is the return on energy calculated and compared against the expenditure? As one can quickly appreciate, the larger, domain-general problem (obtain more energy than one expends) is actually composed of very many smaller problems, and things can get complicated quickly. Pursuing mating rather than food, for instance, is unlikely to result in an organism obtaining more energy than it expends. This leaves the behavioral investment problem – broadly phrased – wanting in terms of any predictive power: why do organism pursue goals other than gaining and energy and under what conditions do they do so? The issue here, then, is not so much that domain-general problems aren’t being accounted for by evolutionary psychology, but rather that the problems themselves are being poorly formulated by the critics.

The next area in this criticism that Gregg stumbles on is the level of analysis that evolutionary psychology tends to work with. Gregg considers associative learning a domain general system but, again, it’s trivial to demonstrate it is not all that general. There are many things that associative learning systems do not do: regulate homeostatic processes, like breathing and heart rate, perceive anything, like light, sound, pleasure, or pain, generate emotions, store memory, and so on. In terms of their function, associative learning systems only really seem to do one thing: make behavior followed by reward more likely than behavior followed by discomfort, and that’s only after other systems have decided what is rewarding and what is not. That this system can apply the same function to many different inputs doesn’t make it a domain-general one. The distinction that Gregg appears to miss, then, is that functional specificity is not the same as input specificity. Calling learning a domain-general system is a bit like calling a knife a domain-general tool because it can be used to cut many different objects. Try to use a knife to weld metal, and you’ll quickly appreciate how domain-specific the function of a knife is.

On top of that, there is also the issue that some associations are learned far more readily than others. To quote Dawkins, “However many ways there may be of being alive, it is certain that there are vastly more ways of being dead”. A similar logic applies to learning: there are many more potentially incorrect and useless things to learn than there are useful ones. This is why learning ends up being a rather constrained process: rats can learn to associate light and sound with shocks, but do not tend to make the association between taste and shock, despite the unpleasantness of the shock itself. Conversely, associations between taste and nausea can be readily learned, but not between light and nausea. To continue beating this point to death, a domain-general account of associative learning has a rather difficult time explaining why some connections are readily learned and others are not. In order to generate more textured predictions, you need to start focusing on the more-specific sub-problems that make up the more general one.

And if doing so is not enough of a pain-in-the-ass, you’re probably doing it wrong.

On a topic somewhat-related to learning, the helpful link provided by Gregg concerning behavioral investment theory has several passages that, I think, are rather diagnostic of the perspective he has about evolutionary psychology:

Finally, because [behavioral investment/shutdown theory] is an evolutionary model, it also readily accounts for the fact that there is a substantial genetic component associated with depression (p.61)…there is much debate on the relative amount of genetic constraint versus experiential plasticity in various domains of mental functioning (p.70).

The problem here is that evolutionary psychology concerns itself with far more than genetic components. In the primer on evolutionary psychology, the focus on genetic components in particular is deemed to be nonsensical in the first place, as the dichotomy between genetic and environmental itself is a false one. Gregg appears to be conflating “evolutionary” with “genetic” for whatever reason, and possibly both with “fixed” when he writes:

In contrast to the static model suggested by evolutionary psychologists, The Origin of Minds describes a mind that is dynamic and ever-changing, redesigning itself with each life experience

As far as I know, no evolutionary psychologist has ever suggested a static model of the mind; not one. Given that evolutionary psychologists is pluralized in that sentence, I can only assume that the error is made by at least several of them, but to whom “them” refers is a mystery to me. Indeed, this passage by Gregg appears to play by the rules articulated in the pop anti-evolutionary psychology game nearly perfectly:

The second part of the game should be obvious. Once you’ve baldly asserted what evolutionary psychologists believe – and you lose points if, breaking tradition, you provide some evidence for what evolutionary psychologists have actually claimed in print and accurately portray their view – point out the blindingly obvious opposite of the view you’ve hung on evolutionary psychology. Here, anything vacuous but true works. Development matters. People learn. Behavior is flexible. Brains change over time. Not all traits are adaptations. The world has changed. People differ across cultures. Two plus two equals four. Whatever.

The example is so by-the-book that little more really needs to be said about it. Somewhat ironically, Gregg suggests that the evolutionary perspective creates a straw man of other perspectives, like learning and cultural ones. I’ll leave that suggestion without further comment.

The next point Gregg raises concerning complexity I have a difficult time understanding. If I’m parsing his meaning correctly, he’s saying that culture adds a level of complexity to analyses of human behavior. Indeed, local environmental conditions can certainly shape how adaptations develop and are activated, whether due to culture or not, but I’m not sure precisely how that is supposed to be a criticism of evolutionary psychology. As I mentioned before, I’m not sure a single contemporary evolutionary psychologist has ever been caught seriously suggesting something to the contrary. Gregg also makes some criticism of evolutionary psychology not defining psychology as he would prefer. Again, I’m not quite sure I catch his intended meaning here, but I fail to see how that it is a criticism of the perspective. Gregg suggests that we need psychology that can apply to non-humans as well, but I don’t to see how an evolutionary framework fails that test. No examples are given for further consideration, so there’s not much more to say on that front.

Gregg’s final criticism  amounts to a single line, suggesting that an evolutionary perspective has yet to unify every approach people take in psychotherapy. Not being the expert on psychotherapy myself, I’ll plead ignorance to the success that an evolutionary framework has had in that realm, and no evidence of any kind is provided for assessment. I fail to see why such a claim has any bearing on whether an evolutionary perspective could do so; I just wanted to make note that the criticism has been heard, but perhaps not formulated into a more appreciable fashion.

Final verdict: the prosecution seems confused.

Criticisms of an evolutionary perspective like these are unfortunately common and consistently misguided. Why they continue to abound despite their being answered time and again from the field’s origins is curious. Now in all fairness, Gregg doesn’t appear hostile to the field, and deems it “essential” for understanding psychology. Thankfully, the pop anti-evolutionary psychology game captures this sentiment as well, so I’ll leave it on that note:

The third part of the game is not always followed perfectly, and it is the hardest part. Now that you’ve shown how you are in full command of the way science is conducted or some truth about human behavior that evolutionary psychologists have missed, it’s important to assert that you absolutely acknowledge that of course humans are the product of evolution, and of course humans aren’t exempt from the principles of biology.

Look, you have to say, I’m not opposed to applying evolutionary ideas to humans in principle. This is key, as it gives you a kind of ecumenical gravitas. Yes, you continue, I’m all for the unity of science and cross-pollination and making the social sciences better, and so on. But, you have to add – and writing plaintively, if you can, helps here – I just want things to be done properly. If only evolutionary psychologists would (police themselves, consider development, acknowledge learning, study neuroscience, run experiments, etc…), then I would be just perfectly happy with the discipline.

Comments are closed.