Saturday, March 12, 2011

Social brains

Here is a foundational question that is worth asking periodically in the philosophy of social science: what is the relationship between the evolutionary history of the human species and our current social and cultural behavior? The sociobiologists had one answer to the question: many of our current social behaviors are an expression, through the medium of the evolved central nervous system, of the compounding of a set of social instincts that were favored by natural selection. E. O. Wilson describes the intellectual agenda of sociobiology in these terms in In Search of Nature:

Much of the new effort falls within a discipline called sociobiology, which is defined as the systematic study of the biological basis of social behavior in every kind of organism, including man, and is being pieced together with contributions from biology, psychology, and anthropology. There is nothing new about analyzing social behavior, and even the word "sociobiology" has been around for years. What is new is the way facts and ideas are being extracted from their traditional matrix of psychology and ethology (the natural history of animal behavior) and reassembled in compliance with the principles of genetics and ecology. ...  With genetic evolution always in mind, sociobiologists search for the ways in which the myriad forms of social organization adapt particular species to the special opportunities and dangers encountered in their environment. (76)
This view sometimes takes the form of a very direct connection from hardwired disposition to behavior. And sometimes it takes the form of a more mediated connection, from selection-favored capacity to complex mental state to behavior. The response we have to a smiling baby falls in the first category, and the "good Samaritan" impulse falls in the latter.

The view at the other end of the spectrum holds with the (relative) autonomy of human thought and action. Human beings are natural biological organisms, to be sure, and our mental capacities are embodied in neural circuitry that has a specific evolutionary history. But what evolution provided us was an all-purpose "reasoning, acting, interpreting" machine that is capable of creating and embodying all cultural and behavioral systems. Much as a computer can embody any algorithm (program), a human brain can incorporate any system of cultural rules. Much as a human child can acquire any human language, so too any human child is a voracious "culture-acquisition device," primed to absorb the cultural rules and meanings around him or her. And once absorbed, it is the cultural program rather than the evolutionary instincts that rule behavior.

These are the polar views of the relation between evolution and culture. I think philosophers and anthropologists may prefer the second story over the first -- philosophers because it creates space for an all-purpose reasoning engine and anthropologists because it gives maximum autonomy to the symbolic and normative workings of freely created culture systems. For both there is the idea that humanity has kicked away its biological origins and limitations. And both are reflexively opposed to the apparent reductionism of the first position.

It seems to me that there is a sturdy intermediate position that incorporates some of both extremes and does a superior job of capturing the truth about human behavior and mind than either. Certainly human cognitive and behavioral capacities have an evolutionary history. But equally, it is plausible that there is a great deal of plasticity and multiple-realizability that has been built into these systems -- with the result that there is no one-to-one relationship between biological origins and current behavioral patterns. Culture is a powerful intervening structure.

Concerning the first point: the evolutionists are surely correct in believing that there is a great deal of brain structure that is responsive to the fundamental situations of human sociality -- family relations, cooperation and competition within small groups, and coordination. These elements of human daily life are too ever-present and too consequential not to have had implications for the evolution of the brain. Moreover, we know that there are highly evolved neural systems for non-social activities and challenges -- finger dexterity, for example, or simple problem solving. And, finally, we have the example of language, which involves both the kinds of latent linguistic structures that Chomsky postulates and the universality of application that results. So it would be surprising if evolution had not shaped the brain around these features of the human condition.

So acknowledging the likelihood of neural structures specific to social life seems pretty compelling. But what specifically? Almost certainly not determinate behavioral routines or dispositions. We surely don't have a gene for "promise-keeping". More credibly, we may have an abstract behavioral disposition for generalized reciprocity; and this may be invoked by a particular cultural system and set of value specifications that give a concrete moral motivation to keep one's commitments and promises.

This is where another important stylized fact about human society comes in: behavior differs widely and persistently across societies, and the best explanation of that fact is the causal efficacy of cultural and value systems that are reproduced within communities of human beings.

We know that those normative and symbolic systems are somehow embodied in persistent human neurophysiology, since all psychological states depend on the brain.  But from the variety of human symbolic, cultural, and normative systems we also know that the neurophysiology that underlies culture necessarily possesses a high degree of plasticity.  Along with the sociobiologists, we can look with favor on the notion that there may be important and contingent features that all human culture systems possess -- at some level of abstraction -- that are the result of constraints in the brain created by our evolutionary history.  But along with the cultural autonomists, we can work on the basis of the hunch that the human brain embodies enough plasticity and capacity for learning to make the role of culture and social norms a credible source of behavioral variation.

(These topics have been considered in earlier posts on human nature (link) and moral psychology (link).)

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