The Liberal Problem with Evolutionary Psychology

I've been a committed liberal, and a committed scientist, for decades. Normally these two world views are pretty compatible. But in years of reading liberal commentary, I've noticed an exception: just about any time somebody brings up the science of evolutionary psychology, you can count on at least a few comments along the lines of "Evolutionary psychology—what bullshit".

If the topic was phrenology, or astrology, such a response would be appropriate. But when we see intelligent people brusquely dismissing entire branches of science, we should look deeper and try to see what's really going on. 

Quick recap: evolutionary psychology is the branch of psychology that looks for evidence of the effects of Darwinian evolution on the human mind. It asks "What are the innate, genetically determined behavioral characteristics and tendencies of humans, and how have they evolved to increase our reproductive fitness?" 

Now, it's not the least bit controversial (at least among people who accept basic science) that evolution has molded the human body. The examples are familiar: walking upright on two legs, developing dextrous hands with opposable thumbs, losing most of our body hair—these things weren't present in our ape ancestors, and evolving them increased our ability to survive and thrive on the African savannah. 

Notice I didn't say "evolving a big brain". That happened, too, and it must have been good for something or evolution wouldn't have built it. The controversy arises over what, if anything, evolution programmed that big brain to do. Is it, as liberals have traditionally argued, a "blank slate", or do we enter the world already equipped with behavioral tendencies? 

For these traditional liberals, evolution only operates from the neck down. The idea that Darwinian forces determine some aspects of our minds and behavior is anathema. 

There are, in fact, excellent historical reasons for this attitude. In the aftermath of World War II, scientists and intellectuals were so appalled at the Nazi experiments in human breeding, not to mention genocide, that any influence of genetics on human capacity or behavior had to be denied. Opening the door—even a crack—to this possibility was seen as endorsing the idea that eugenics might be a worthwhile endeavor, and, even more disturbingly, that there might be (as racists had claimed all along) actual genetic differences between the races in things like intelligence and aptitude. Therefore, in academia and elsewhere, the entire subject became unmentionable. It was a matter of liberal dogma that human personalities were entirely determined by culture and upbringing: the young child's mind was indeed a blank slate, and it was the job of society to write good things on that slate. In the ongoing "nature vs. nurture" debate, nurture won round one decisively. (What every parent knows—that each of their children came into the world with a completely different personality—was denied as an error due to a nonscientific outlook.) 

This had lots of consequences. One that particularly rankled conservatives was the oft-expressed notion that criminals weren't really responsible for their misdeeds: their bad behavior was somehow society's fault. Liberal social scientists were left looking for the "root causes" of crime and other dysfunction, and proposing ambitious social programs to overcome them in at-risk individuals. 

In retrospect, it was only a matter of time before a few scientists began questioning the blank slate assumption. Why, they asked, if evolution can shape bodies to be more successful reproducers, can it not also shape minds to do the same thing? In fact, by the relentless logic of evolution, wouldn't it have to? Certainly plenty of other animals have innate behavior—why not us? So they started looking for innate "universals" of human behavior. And finding them.

One of the first things they zeroed in on, and still perhaps the thing that draws the greatest ire of the anti-evolutionary-psychology crowd, was human sexual behavior. To a great degree, this comes down to the question that we presume women have been asking each other since time immemorial: why are men such pigs?

The basic evolutionary argument isn't hard. It starts from the simple observation that the roles of men and women in reproduction are dramatically different. While it's theoretically possible for a man to father a new child every day, a woman can generally produce no more than one baby a year. And while a single ejaculation may produce hundreds of millions of sperm, a woman produces but one egg a month. Sperm are cheap, and eggs are precious. So if the impetus of the genes we carry is—as evolutionists recognize—to maximize the number of copies passed on to future generations, the optimum reproductive strategies of men and women must be different. Women must do everything they can to assure that their few children are raised to become successful, reproducing adults. Men must do everything they can to maximize the number of children they father who have at least a chance of reaching maturity.

Since raising children is hard, women try to establish a stable pair bond with a man to share the responsibilities. Since men have no evolutionary reason to raise children that aren't their own (or, to a lesser extent, those of close relatives) they will insist on exclusive sexual access to their mates, even as they remain on the lookout for opportunities to spread their genes with other partners. In other words, they act like pigs.

If some of this seems doubtful, it's only because I don't have the time or space to tell the whole story. There is much, much more to it, and books like Steven Pinker's The Blank Slate tell it much better than I can.



Are you one of those people who thinks evolutionary psychology is bunk? Think carefully before you answer, because you need to understand what a "yes" would mean.

I'm going to assume that you believe the basic tenets of evolutionary theory; if you didn't, you likely wouldn't be reading this. But in order to say that evolution is cool but evolutionary psychology isn't, you must necessarily believe at least one of the following:

• It is impossible for genes to affect the workings of the mind, OR
• How our minds work has no effect on our reproductive success

Because here's the thing: if you accept that evolution is real, and if you accept that genes can affect human behavioral tendencies, and if you accept that how we behave can affect our reproductive success, then you simply don't have any logical choice but to believe in evolutionary psychology.

So if you don't believe in evolutionary psychology, let me ask you: what part of the above don't you believe?

If you're a traditional liberal, perhaps it's the part about genes influencing personalities: you subscribe to some version of the Blank Slate idea. Most people, in fact, do. But there's a big problem: some years ago, Judith Rich Harris produced a landmark book, The Nurture Assumption (second edition), in which she showed that all the social science research on the effects of upbringing on molding personality was fatally flawed, because it failed to control for the effects of heredity. After exhaustive analysis, Harris was forced to conclude that about half of the variation in adult personalities was due to our genes, and the other half was due to something else, not parental influence. She hypothesized that this "something else" was mostly the influence of the child's peer group, which in fact fits observations quite well.

If you're like most people, right now you're saying "That can't be right—parenting obviously matters a lot!" Well, sorry, either you accept science or you don't. Rather than try to argue with you, I'll just say: read Harris's book.

Here a brief digression is in order. Over 30 years ago, the much-vilified evolutionist Richard Dawkins wrote a landmark book called The Selfish Gene. It was a brilliant work that still reads well today, but predictably it was completely misunderstood, especially by non-scientists who didn't like what they thought were its conclusions. 

Dawkins' basic premise was simple: starting with the earliest life forms, what genes did was replicate: make copies of themselves. This simple fact kicked off the whole process of evolution, because if one random variant of a gene was a bit more successful at copying itself, its burgeoning offspring would soon crowd out the less-successful replicators. Therefore, only the most "selfish" genes lived to replicate another day; other variants would be ruthlessly weeded out. 

As evolution progressed, genes acquired the knack of building what Dawkins called "survival machines" and what we call "bodies". In his famous formulation, a body is a survival machine put together by a short-lived coalition of long-lived genes. It is, in fact, our genes that carry our inheritance down the many generations; our ephemeral bodies are just useful vessels for the genes to temporarily ride in and carry out the dance of replication. 

Now, dear reader, please pay close attention. Dawkins was savaged because his idea was interpreted as claiming that all creatures, humans included, are necessarily selfish. He said no such thing. In fact, he took pains to point out that it is entirely possible for selfish genes to build an organism that behaves unselfishly. He even explained how this could (and apparently did) happen. To give just one quick example: a bird that unselfishly risks revealing its location by sounding an alarm when it sees a predator threatening its flock has a very good genetic reason for doing so: many of the other flock members carry the same "selfish" genes as it does, and ensuring the survival of the flock results in more copies of those genes surviving, even if the bird doing the alarming gives up its own life.