Henrich

It may be that the newer information is bending me back toward admitting some environmental influence on human behavior beyond incentives and trauma, which I have always acknowledged had good supporting evidence. I was prepared to be grumpy that even Joseph Henrich (The WEIRDest People In The World) has been moved for social reasons to avoid the full genetic understanding because of the nearby toxicity of racial and male/female controversies. That is not what he is arguing, however, and he makes a decent case for an interplay rather than a compromise between the factors. There has always been a trivial observation, that a gene just sitting there on a table doesn't produce any behavior, nor does an environment without an organism. But that is not the same thing as the organism changing the environment which changes the organism.  Sociogenomics describes this as more of a Mobius Strip of co-influence. (More on this below.) I love mathematical analogies and have little defense against their charm.

Pairing this with my recent post on everyone else focusing too much on the worst of the other side's arguments, I see that I have done this with the arguments for environment.  I have spent my energy on annoyance at research that draws conclusions about probable environmental effects when it does not even address some obvious heritable explanations. I try to stay away from the controversies altogether until people are proposing expensive, inconvenient, and ill-thought-out solutions to problems of education. "Research shows that schools with newer textbooks have higher test scores." Um, richer districts have smarter kids to begin with. You have to correct for that with proper controls. "If there wasn't so much stigma about (blank)/ if (blank) students could see more people like themselves/ if we made them all play cooperative games..." It's maddening.

Henrich is talking about a much longer game. Homo sapiens seems to have outcompeted the more individually intelligent Neanderthals with shared cultural knowledge.  We stored the necessary information for survival in each other. This much I knew, albeit only recently. Yet more deeply, there are varieties of collective brain. In very stable environments, the tribe might as well move in the direction of coding ever more information in the genes.  At the other extreme, a more volatile environment requires brains that are better at novel problem solving. No human group has ever been at either extreme - we are talking about gene frequencies in a population, not replacements. The rate of change in an environment changes the gene frequencies over time, push-pull.

The balance between these poles is in cultural/institutional knowledge. These are things the group knows, but may not know why or how they know. He gave an example of ten necessary steps for one tribe's preparation of beans. If you don't get all ten steps right, you increase the chances of cyanide poisoning, quickly or slowly. All of the women and many of the men knew the proper steps. But for a few steps they had no explanation. "This is just the proper way to make beans.  It is our custom." Humans in many places have lost the ability to make bows-and-arrows and not reinvented it for centuries. The technology has been reinvented many times. 

Necessity may be the mother of invention, but tradition, custom, and religion are the mothers of preserving knowledge. Once something is good, changing it almost always makes it worse. This is true even at the physical level, that most mutations are deleterious. Preservation is usually more important.  But in case of invasion, or the mussels or birds suddenly being in short supply, the group has to be willing to try new things, and someone has to think of new things to try. This may drive the development of long-term memory or longevity beyond prime fertility as well, that someone recalls rather than invents a new idea.

Or...it may drive the ability to sing songs and tell stories and develop ceremonies to hold the collective wisdom in condensed, shared form. 

Increased pathogen load depresses intelligence in the individual, but probably not potential intelligence even on a long time scale. Reducing pathogen load depends on innovation, but far more on custom and tradition. Not only can one learn more when young, one can live longer to pass knowledge of berries, or spoor, or weather along to the others. The ceiling may be little changed. 

As I was absorbing this, the NYT had an article on sociogenomics that touched on these matters on much shorter and individual time scales.  I pass this along a bit more reluctantly. Two bits of information contained in it I have seen refuted.  I don't know enough to discern whether it is Conley or his opposition is right, so I won't enter in to an argument that is over my head. But the suspicion caused me to look at other pieces more skeptically, wondering "But couldn't that also be explained by...?" Network effects are tricky, because sample sizes are often too small for confidence. It's a good article nonetheless and valuable even if flawed.