This is the first of a series of posts on the biology of gender. This is a research interest of mine, and generally has a big part in my teaching as well.

Behavioral biology seeks to understand behavior in an evolutionary framework. The widely held central dogma of evolutionary biology is that selection works on allele frequencies. This leads to simple models of behavior that assume behavior is acted on by selection, and that underlying alleles are selected for or against over time. This sort of logic can be seen in biological racist doctrine, sexist racist doctrine, and more politically ambiguous research such as the famous twin studies, and about every other article in journals such as “Evolution and Human Behavior” (not that I have anything against that journal in particular … but … well, you’ll see…)

When thinking about the biology of behavior, a common guiding principle is that the stronger the effect, the “more biological” it is. There is a certain logic to this. If a certain aspect of, say, human behavior is observed over and over again, across cultures, and it is shown to persist even when social, economic, or cultural influences seem to work against it, then it makes sense that it is somehow predetermined. Predetermined means hard wired, or built in, or genetic, or instinctual.

For example: Females (XX Chromosomal complement) typically have the babies, while males (XY) typically do not. That’s pretty simple.

But what about behaviors less constrained by physiology? Like the ability to run a nation, moral reasoning, intelligence or talent in certain areas?

I want to question the principle that strength or persistence of an effect correlates to the degree to which it is caused by genes. Or, more precisely, that variance in an effect is highly correlated to allelic variation.

Consider a reasonable list of gender differences, and rank or rate these differences with respect to how persistent or stable they are. Classic examples might include mathematical abilities or verbal abilities. (In the former, boys excel, in the latter, girls excel, in many data sets, according to widely held beliefs).

Given this list, the persistence of the trait should predict the degree of genetic causality even if we cannot describe the causal chain of events that leads to the effect. So sex differences in interest in football would be different from sex differences in having babies. So far so good.

Now consider the example of first (given) names (Mary, Bob, Alfonzo, etc.). In a typical human culture, there are names that are given to boys, and names that are given to girls. Thus, a person’s name typically identifies a person’s chromosomal makeup, or sex, which in turn is closely related to gender.

This is a very strong effect. Yes, there are exceptions and counter-examples, but the effect is much much stronger than, say, differences in math ability or differences in verbal ability. The strength of this effect is so strong that, following the logic we’ve laid out so far, one MUST agree with this statement:

“To whatever degree sex differences in math or verbal abilities are genetic, sex differences in first names must be more genetic.”

This, of course, creates a problem, because it is difficult to figure how genes code for first names. The only way to link first names with genetics is through a very indirect route that must involve all sorts of other aspects of human behavior. For instance, it may be important to identify individuals’ sex by first name so you don’t accidentally agree to marry someone of an inappropriate (for you) gender. Therefore, even though the specific names (Mary vs. Bob) are not coded for by genes, having gendered names is.

(Someday I hope to assemble several explanations of this form and write a book called: “The Idiots Guide to Backpedaling”)

The most likely explanation for gendered names and their persistence is that sex and gender are important. The same explanation can be applied to other sex associated patterns such as clothing and the color you paint the baby’s room. All of these features of human behavior are highly culturally constrained … many cultures do not have a room into which one ensconces the baby … but some are more widespread, such as personal adornment, clothing, and yes, first names, yet the details of the “trait” are highly variable across cultures.

Is it the case that if we rank these cultural trappings of sex or gender identification by cross-cultural persistence, that we have also ranked them by degree of allelic causality? Unlikely. Is it the case that I am presenting you with a red herring … that there are behaviors that are indeed linked to genes that differentiate by sex (like math or verbal ability) and others that are not (like clothing, adornment, names, etc.)? Well, maybe, but my point is that we don’t have a way of knowing this at this time.

In order to argue that some traits are “genetic” and others are “cultural” it is necessary to have a a way of a priori differentiating between human behaviors that are in one category (allelic) vs. another (non-allelic, cultural). It is not OK to make this distinction post hoc based on one’s incredulity regarding genetic causality. Otherwise, the decision to call one trait “genetic” and another “cultural” quickly becomes a political act. Bad scientist…

It is possible that the distinction between these kinds of behaviors … genetic vs. cultural (or any other phrase you like for the bio-cultural dichotomy) is itself a falsehood, or at best, a construction that has very limited use and a great deal of power in misleading us in our thinking about behavioral biology.

I offer these thoughts as a preface to a longer argument, but I’ll give you the end point of this line of reasoning right away: I don’t feel that behavioral biology is distinct from the social sciences (such as Cultural Anthropology). Rather, I feel that most or all of the social sciences are subfields in the overarching and very powerful area of behavioral biology. Yes, I admit it up front: I have a plan to take over the world!!! (or at least, colonize all of the subfields…)

Have you read the breakthrough novel of the year? When you are done with that, try:

In Search of Sungudogo by Greg Laden, now in Kindle or Paperback
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