“Behavioral genetics” is a science that seeks to demonstrate a physiological and genetic basis for human behavior—for liberalism versus conservatism and for religion versus irreligion, among countless other traits.
Some of it is well established, though not known to the general public, and other parts more-or-less established. Inevitably all of it is attributed to evolution and natural selection, the relevant discipline being called “evolutionary psychology.” The more serious devotees insist that all human traits are heritable—i.e., genetic—as well as derived by natural selection.
Perhaps because I am genetically obtuse, there are parts of the evolutionary tale that I don’t understand. Herewith some questions I am powerless to answer, in hopes that someone will help me. I look for concrete, demonstrable, provable answers, not vague, speculative, metaphysical ones.
(1) I do not understand populational altruism from the standpoint of behavioral genetics or evolutionary psychology. Populations in numerical decline—the French, for example—intentionally import genetically very distinct and faster-breeding peoples. Sweden, perhaps the whitest of nations, deliberately imports black Africans, and Germany, Moslems. The United States focuses its domestic policy on the upkeep of a black population.
What selective pressures bring this about? What is the reproductive advantage for the host populations? And since all traits are genetic, not having children must be the result of natural selection. That is, the reproductive advantage of not having children was so great that it spread rapidly through whole populations.
(2 ) Human evolution is said to be “ongoing”, and “both copious and rapid.” While any dog-breeder can attest that selection, natural or otherwise, can produce great genetic changes, I wonder why 2500 years of this rapid natural selection haven’t.
Romans and Greeks in the statuary of Praxiteles and Phidias, as well as Roman copies of Greek works, look just like us. Writers and thinkers of classical times both in style and cast of mind read like moderns: Plato, Xenophon, Aristotle, Archimedes, Julius Caesar, Ovid, Papinian, Ulpian, all the gang. The sense of humor is the same: Juvenal could be Mencken’s (very) long-lost brother. The ancients spent their time as we do, making war on anyone within reach. Twenty-five hundred years of rapid evolution seem to have produced a net of zero.
(3) Does not rapid evolution require intense selective pressure? What are these pressures? That is, pressures strong enough to cause greater rates of reproduction? In societies such as the white European, nearly everyone marries, nearly everyone has small families, and nearly everyone lives past reproductive age. This would seem to reduce selective pressures based on differential rates of survival and reproduction.
Would not such evolution as still occurred do so through things like assortative mating, in which for example the smart marry the smart, producing a caste of the increasingly bright? Do not liberals marry liberals, and conservatives conservatives, thus concentrating the genes for their respective furies? One does not easily imagine Bernie Sanders (or anyone, for that matter) marrying Ann Coulter.
(4) I do not understand the behavioral genetics of sexual selection.
For example, why do women have breasts? They are, as we say, a waste of metabolic resources, unnecessary for nursing young (neither chimps nor dogs have breasts except when nursing), and make running difficult (we have sports bras for a reason). That is, they are both useless and detrimental. Why do they remain in the population?
Well, see, it’s because men like them. This allows well-endowed women to mate with better men, and have more offspring. (The idea that a comparatively planar women can’t get laid suggests that behavioral geneticists need to get out more, but never mind.) Then why in 2500 years have not big hooters become general in the population? Or even common? And of course if they did become general they would lose their selective advantage since all women would have them. They would then constitute a species-wide disadvantage.
As a minor matter, I do not see how the masculine preference for big ones came about. In a population of cave people with flat women, presumably the response to the mutational appearance of biggies would have been, “Geez, Urk Urk, what’s wrong with Sally?” “Beats me, Ralph. Maybe it’s cancer.”
That is, big breasts would only be an advantage in the presence of a preexisting preference for them. But why a preference before there was anything for it to prefer?
(5) It seems to me that evolution currently takes place chiefly not through selective pressures but through the lack of them. For example, diabetes is said to be becoming much more common in because medicine keeps diabetics alive long enough to reproduce. Another example is intelligence, which is said to have fallen fifteen points of average IQ because the stupid dysgenically have many more children than the smart. (Of course, proponents of the Flynn Effect say that IQ has risen fifteen points. Either would have had huge observable effects, and hasn’t, but never mind.)
In short we are seeing the survival of the least fit, in both individuals and races, which seems a bit bass-ackward in Darwinian terms. And, again, since all traits are genetic, failure to reproduce and the encouragement of deleterious traits are products of natural selection.
(6) If traits that make for survival spread through a population, it follows that traits that do not spread do not make for survival. These would seem to include intelligence, physical prowess, and acute senses. Genes exist in the population—mutations not needed—for the phenomenal physical plant of Mohammed Ali, the intelligence of Hawking, the eyesight of Ted Williams, and so on. They remain exceedingly rare, and not obviously more common than they were in the time of Thucydides.
Meanwhile, traits of little or no advantage do become general. The epicanthial fold, for example, which makes the Chinese slant-eyed. This is said to be of advantage in survival by, according to who you talk to, either conserving energy or protecting the eyes from icy winds. I am unaware of actual evidence for either, but then I am unaware of many things.
If any advantage exists, it is vanishingly small. Do we really believe that people with squinty eyes had more children than the merely round-eyed?
(7) I do not understand the concept of the “dysgenic” and the “eugenic.” Both seem to imply value judgements–that evolution is going in a good or a bad direction. This smacks of teleology, entelechy. I thought evolution had no direction and that it could be neither good nor bad. It is the mindless, undirected adjustment of a system to its circumstances.
For example, the anthropologist Peter Frost argues, perhaps correctly, that North Europeans have become less violent because the hanging over centuries of violent criminals has reduced the genetic tendency to violence. He regards this as an improvement—as do I, if it has happened. But how is it an improvement in the sense of evolution, which has no such conception of betterment?
(8) Again, some behavioral geneticists assert that all human behavior is heritable—i.e., is to a large extent determined by genetics. Our behavior changes as our genes evolve. Weill, all right. You can breed dogs to be aggressive or friendly.
Yet obviously many sorts of human behavior change far too profoundly and rapidly for natural selection to be responsible. For example, Europe has gone from very to barely religious, sexual mores in America from highly restrictive to anything goes, family size in Mexico from fifteen-and-starve to two-and-university.
This, say the genetic determinists, happens because genes express themselves differently in different environments: same genes but different circumstances.
This means, if I do not misunderstand them, that genes (inferred rather than demonstrated) for one behavior are, under the influence of unspecified changes in the environment, genes for precisely opposite behavior—from belief to disbelief, large families to small, prudishness to libertinism. And what pressures cause this turnaround?
Yes. If a Mexican girl from a family of fifteen moves into the middle class and gets a refrigerator (and simultaneously the means to support a large family of her own) she has two children and sends them to university. Here is a fruitful field for further study: The Darwinian effects of Kelvinators. Exactly how kitchen appliances drastically alter the expression of genes for reproduction eludes me. It is also curious that prosperity is a contraceptive: Reproduction is inversely proportional to the means of supporting it.
Clearly I do not understand evolutionary psychology. This, I suspect, can equally be said of evolutionary psychologists.