Evolution by Cultural Selection, and Human Tribalism

 Carl Safina has written fascinating accounts of animals and how they live, communicate, and educate their offspring.  His latest book, Becoming Wild: How Animal Cultures Raise Families, Create Beauty, and Achieve Peace, is full of interesting revelations.  One of the topics he discussed involved the creation of new species.  Scientists have long recognized that evolution can allow animals living in isolated regions where no mating is possible with other groups to follow different paths and develop different body features and differing cultures.  Safina was intrigued by examples of animals who shared a location yet still seemed to be evolving in different directions.

“The existence of hundreds of species of cichlid fishes in the same African lake has always seemed to me proof that some other process is functioning in the world.”

What Safina needed to find was some mechanism by which, in a given species, groups will choose to not interbreed even though they might intermingle.  His best example is the orcas who live in the Pacific Northwest.

“Think…for instance of the killer whale types who inhabit the same region but specialize in hunting prey in different ways—catching fish in one case, mammals in another—and have consequently developed social and physical differences.  Regardless of the fact that scientists haven’t named these whale groups separately (yet), they avoid each other and really have become separate species.”

Safina finds other examples of species in which cultural differences develop and lead to the tendency to avoid mating with those having different cultural attributes.  He arrives at this conclusion.

“I strongly suspect that the mechanisms driving the origin of new species are mainly three: Charles Darwin’s ‘natural selection’ and his ‘sexual selection,’ and the one our present exploration has brought us to here, which I’ll call cultural selection.  By cultural selection I mean the power of socially learned preferences to create group cohesion and cause avoidance between groups.  The avoidance means reproductive isolation.  The reproductive isolation sets groups up for different journeys.  Cultural learning can cause groups to mate like with like, thus deepening specializations, amplifying differences, and, I believe, diverging until they are sufficiently distinct to be different species.”

Safina’s ruminations about the evolution of animal species bring to mind a related dynamic that is operative in human societies, particularly with regard to political divides.  Political analysts continually refer to our development of quite different political cultures as tribalism.  We already separate ourselves into red and blue regions, minimizing contact with our political enemies.  We have even begun to avoid genetic mixing.  In previous generations, there did not seem to be much concern about the politics of whoever one’s child was marrying, but that has changed.  The Institute for Family Studies put out this note in 2020: Marriages Between Democrats and Republicans Are Extremely Rare.

“Marriage has always been a marker of both social solidarity and division in America. Marriages between people of different races were once prohibited, but they are now on the rise – one indication of growing solidarity across racial lines in America. Tolerance toward interfaith marriages has also grown over the years, and Americans are more likely to marry a spouse of a different religion now. But the same cannot be said for politics.”

The term “mixed marriage” in this context refers to marriage between an avowed independent with a party member.  Pundits have doubts about how many “independents” are truly independent rather than possessing a rigid voting pattern. 

“…it is possible to make a direct comparison between 2020 and 2017, the earliest year when the spouse’s party affiliation was available in the American Family Survey. My analysis suggests that in just three years, the share of politically-mixed marriages in the U.S. has declined from 23% to 21%, and the share of marriages between a Democrat and a Republican dropped from 4.5% to 3.6%.”

Using marriage as a simulant for mating and acculturation is not as reliable as it once was, but it is as good as any available.  These data suggest there is a component of genetic enhancement of particular attributes in isolated political cultures.  We usually think of evolution as a slow process taking place over long periods, but it can occur faster than one thinks.

In 1959, a group of Russian geneticists began what is known as The silver fox domestication experiment.

“Today the domesticated foxes at an experimental farm near the Institute of Cytology and Genetics in Novosibirsk, Siberia are inherently as calm as any lapdog. What’s more, they look eerily dog-like. All of this is the result of what is known as the silver fox, or farm fox, domestication study.”

“Starting from what amounted to a population of wild foxes, within six generations (6 years in these foxes, as they reproduce annually), selection for tameness, and tameness alone, produced a subset of foxes that licked the hand of experimenters, could be picked up and petted, whined when humans departed, and wagged their tails when humans approached. An astonishingly fast transformation. Early on, the tamest of the foxes made up a small proportion of the foxes in the experiment: today they make up the vast majority.

After six generations they had developed specimens with the behaviors of a different species; physical change to another species would take longer.  How much change occurred in one generation?  In two?  In three?  What generation of cultural isolation are we in…second?  How much has our political system changed in the last generation?  How much will it change in the next? 

We could be heading for World War III, or Civil War II, or both.