December 19, 2008

Fallacies of Evolutionary Psychology @ Scientific American

Scientific American has an article on Evolution of the Mind: 4 Fallacies of Psychology. The Coda of the article:
Among Darwin’s lasting legacies is our knowledge that the human mind evolved by some adaptive process. After all, the human brain is even more costly to run than an internal-combustion engine these days, consuming 18 percent of the body’s energy intake while constituting merely 2 percent of its weight. We wouldn’t have such an organ if it hadn’t performed some important adaptive functions in our evolutionary past.

The challenge for evolutionary psychology is to move from this general fact to some evidentially well-supported specifics about the adaptive processes that shaped the mind. But, as we have seen, the evidence needed to substantiate accounts of adaptation in our lineage during the past couple of million years is scarce. And this isn’t the kind of evidence that is likely to materialize; such evidence is lost to us, probably forever. It may be a cold, hard fact that there are many things about the evolution of the human mind that we will never know and about which we can only idly speculate.

Of course, some speculations are worse than others. Those of Pop EP are deeply flawed. We are unlikely ever to learn much about our evolutionary past by slicing our Pleistocene history into discrete adaptive problems, supposing the mind to be partitioned into discrete solutions to those problems, and then supporting those suppositions with pencil-and-paper data. The field of evolutionary psychology will have to do better. Even its very best, however, may never provide us knowledge of why all our complex human psychological characteristics evolved.
I do have a distaste for popular evolutionary psychology, not because I don't think that a lot of human behavior is genetically defined and the result of adaptation (I do), but because the evidence for this adaptation is simply lacking.

We neither know how the brain works, nor how genes influence the way it works. Nor do we have a good quantitative handle on human behavior. Some aspects of it (general intelligence, for example) are better known than others, but a lot of psychology is more akin to opinion than to deep knowledge.

So, it seems that making a convincing case for adaptation in human behavior will remain a difficult problem for some time, and evolutionary psychology must find a way to go beyond hypothesizing towards hypothesis testing. The study of present day human genetic-behavioral variation will be invaluable to that end, although it will require us to overcome the idea of the human mind as more-or-less a finished product of the Paleolithic, and accept the idea of continuing and perhaps intensifying evolution.


Jason Malloy said...

I do agree with one of Buller's subtexts that evo psych gets less solid when it distances itself from primatology, differential psychology and behavior genetics, though I must say, that article was way too long for how few illustrative cases he was able to present for "evo psych gone bad".

The best criticism was using gay men to challenge greater innate male sexual jealousy. This does suggest jealousy cues are more facultative than sex dependent. But it isn't obvious why the evolutionary prediction was flawed. If sex-stereotyped defenses provided even a small, average reproductive advantage, as they logically do, it seems reasonable to expect such cognitive tendencies to spread. (it's not like our male ancestors had to navigate gay relationships, so it is not obvious why they should be this flexible. OTOH Buller does not cite a source on gay jealousy; perhaps the dynamics are not representative or as presented.)

Gradient said...

Some of my questions re evo psych, or more specifically neuro-physiology (can be determined with imaging so should be easy to test) is do various human populaitions populations tend toward different regions of their brains being more active, or a bigger volume in ratio to overall volume? I'd venture to guess that due to heat produced, populations from colder regions would have more of their brain function in beta and gamma frequencies more often, which would mean generally more neo cortical activity. That could be a liability in hot climates, where alpha and even theta oscillations, that produce less heat, would be desirable. Since certain regions, take limbic for example, function in theta-alpha oscillations, Id be willing to bet they are more often dominant centers in tropical populations. As to avg volume difference of region, we know such exists for sexes, it is likely that such is also the case for population groups with several tens of thousands of years variation in where they lived. If this is not the case it would be interesting to see what was. Im sure this study would get some up in arms though, lol.