Genes and the Adapted Mind
Humans have a dual inheritance system, one genetic, one cultural. A critical issue is the nature of gene-culture co- evolution. Sociobiologists have insisted that biology is dominant. E. O. Wilson puts this in a bold, if somewhat loose, metaphor: “The genes hold culture on a leash. The leash is very long but inevitably values will be constrained in accordance with their effects on the human gene pool. The brain is a product of evolution. Human behavior–like the deepest capacities for emotional response which drive and guide it–is the circuitous technique by which human genetic material has been and will be kept intact” (1978, p. 167; Lumsden and Wilson, 1981, p. 13, p. 179). In earlier Metanexus essay, I found the “selfish gene” metaphor problematic; here again, microscopic genes cannot hold any leashes.
There needs to be rigorous analysis of the analogy before we know whether this is science, philosophy, ethics, or poetry, or what the truth claims are.
More scientifically put, the claim is that, although there are many options in culture (a long leash), genetic constraints always circumscribe and overrule human behavior. “The central tenet of human sociobiology is that social behaviors are shaped by natural selection” (Lumsden and Wilson, 1981, p. 99). This is “the general sociobiological view of human nature, namely that the most diagnostic features of human behavior evolved by natural selection and are today constrained throughout the species by particular sets of genes” (Wilson, 1978, p. 43). A quite simple biological force– producing the most offspring in the next generation–pervades and is the most basic determinant in all human affairs.
But a simple biological force will have difficulties governing a complex brain. The number of neurons and their possible connections is far vaster than the number of genes coding for the neural system, and so it is impossible for the genes to specify all these connections. When there emerges a later-evolved method of communication at the neural past the genetic level, the genes will need subsequently to develop so as to favor teachability above all.
What will get selected is not so much specific gene traits co- evolving lockstep with matching cultural behaviors, but open teachability, which is to say that the genes will have to abandon tight control of behavior and cast their luck with launching a human organism whose behavior results from an education beyond their control.
As more and more knowledge is loaded into the tradition (fire- building, agriculture, writing, weaponry, industrial processes, ethical codes, electronic technology, legal history) the genome selected will be that set that is maximally instructible by the increasingly knowledgeable tradition, and this will require that the genes produce a flexible and open intellect, generalized and unspecialized, able to accommodate lots of learning and to do so speedily, able to adopt behaviors that are functional in, or conform to, whatever cultures they find themselves in.
One of the best of the geneticists, Theodosius Dobzhansky, saw this: “A genetically fixed capacity to acquire only a certain culture, or only a certain role within a culture, would however be perilous; cultures and roles change too rapidly. … Human genes insure that a culture can be acquired, they do not ordain which particular culture this will be” (1963, p. 146). It is better to be able to learn any of the myriad human languages than to be genetically dispositioned to learn French, better to be able to use any of various cultural ideas than to be genetically inclined to use only Polynesian-originated ones.
Intelligence, based on neurology, allows an organism to make an appropriate, rapid response to an environmental opportunity or threat, protecting the organism against the necessity of making slower, less reversible responses at the genetic level. If the genes supply intelligence in sufficient amounts, the genes need not themselves be closely tuned to directing behavior that can track environmental changes; they turn this over to the general intelligence they have created. Robert Plomin, in an analysis of human development and genetics, concludes, “There is no evidence for major-gene effects on normal variation in general or specific cognitive abilities” (1990).
S. L. Washburn, surveying the archaeological record, concludes “that there has been no important change in human abilities in the last 30,000 years” (1978, p. 57). If so, then all the changes are technological, historical, political, religious, or some other form of cultural change. In present human populations, it seems that a baby taken from any race on Earth, appropriately reared, can receive almost any sort of general education. This does not mean that any baby can become a mathematician, or musician, or professional basketball player. But different babies can be found in any particular race that can do all these things well, and any normal baby can learn enough of these things to function more or less normally in any culture.
This idea of a “global learning capacity” can be exaggerated, however. The genes do not build a “tabula rasa” mind; humans do need behavioral dispositions of some kinds (to fear snakes or spiders, to seek mates, to avoid incest, to protect their children, to reciprocate for mutual benefits, to obey parents or follow leaders). Boyd and Richerson further suggest that humans could be genetically disposed toward religious beliefs or toward ethical practices, because of cultural group selection; those in such cultures prosper (1985, pp. 175-177). So a genetic bias toward ideas useful in various cultures can be expected, and welcomed.
The sociobiological model of the mind seems rather too simplistic. More recently it has been replaced by an account from evolutionary psychology. This finds that humans have not so much an all-purpose or unified mind as what John Tooby and Leda Cosmides call an “adapted mind” made up of “a complex pluralism of mechanisms,” “a bag of tricks,” a set of “complex adaptations” that, over our evolutionary history, have promoted survival. “What is special about the human mind is not that it gave up â€˜instinct’ in order to become flexible, but that it proliferated â€˜instincts’– that is, content-specific problem-solving specializations” (Tooby and Cosmides, 1992, p. 61, p. 69, p. 113). “These evolved psychological mechanisms are adaptations, constructed by natural selection over evolutionary time” (Cosmides, Tooby, and Barkow, 1992, p. 5).
These form a set of behavioral subroutines, selected for coping in culture, by which humans maximize their offspring. Cosmides once started a lecture by holding up a Swiss army knife as a model of the mind, at a joint meeting of the Royal Society of London and the British Academy in London, 1995. The mind is a kit of tools for this and that, rather than a general purpose learning device. Humans have needed teachability, yes, but they have also needed channelled reaction patterns. The adapted mind evolved a complex of behavior-disposition “modules,” “Darwinian algorithms,” each dedicated to task-specific functions in this or that dimension of life, such as picking mates, or helping family, or obeying parents, or being suspicious of strangers, or dealing with non- cooperators by ostracizing them, or preferring savannah type landscapes. In picking mates, for example, men are disposed to select younger women, likely to be fertile. Women are disposed to select men of social status, likely to be good providers. Further, these dispositions to behavior, present still in any contemporary culture, are those that meant survival in a Pleistocene environment (such as fear of strangers, or desiring many children); and this may mean that they are neither optimal nor altogether desirable dispositions in a modern environment (where people may need to cooperate with strangers, have fewer children, and live in cities.
The human mind is indeed complex, and various subroutines to which we are genetically programmed (caring for children, obeying parents, and even ostracizing non-cooperators or being suspicious of strangers) may indeed be convenient shortcuts to survival, reliable modes of operating whether or not persons have made much rational reflection over these behaviors. Some more or less “automatic” behavior is desirable. It is hardly surprising that males look for a female likely to be a good mother (able to bear children and care for them) and females look for a male likely to be a good father (able and likely to provide resources and to care about his family). It would be surprising if evolution had selected any other dispositions.
Nevertheless, though there is something to be said for behavioral modules, the mind is not overly compartmentalized, because behaviors interconnect. If women are prone to choose men of status, that requires considerable capacity to make judgments about what counts as status, economically, politically, religiously. They will have to judge which one, from among their suitors, often still relatively young, is most likely to attain it in the decades of their child-rearing. If men are to be good providers, that requires judgments about cooperation, and if one is operating in a barter or market culture, judgments will be needed about trading with strangers, or ostracizing merchants who renege on their promises. Men need to judge potential mates not just on their likely fertility, but on whether they too are likely good providers, able and willing to care for offspring, and to educate them successfully into their culture, until they reach childbearing age.
Any such articulated behavioral modes need to be figured back into a more generalized intelligence. Genetically programmed algorithms seem unlikely for the detail of such decisions under changing cultural conditions. Such decisions are difficult even for well educated persons; they may require insight into character and evaluation based on intuition, additionally to conscious, explicit calculations; decisions at this level take considerable capacity for judgment, not simply mental mechanisms. The strongest finding by far in the cross-cultural study of mate preference is that both sexes from cultures around the globe consistently agree on the most promising characteristics they look for in a mate: kindness, understanding, and intelligence (Buss et al, 1990, pp. 18-20). Capacities to select such a mate are perhaps somewhat “instinctive,” but they are unlikely to be an adaptive mechanism isolated from general intelligence and moral sensitivity.
Apparently, the mind is not so compartmentalized that humans– modern ones who read this literature at least–cannot make a critical appraisal of what behavioral subroutines they do inherit by genetic disposition, and choose, if they wish, to offset these “Stone Age” dispositions in their evolutionary psychology.
Cosmides and Tooby are doing just that–if we may be permitted an ad hominem argument. They themselves illustrate that the human mind is more than a patchwork of naturally selected response routines when they call for “conceptual integration” of the diverse academic disciplines studying humans, their behavior, and their minds. These include “evolutionary biology, cognitive science, behavioral ecology, psychology, hunter-gatherer studies, social anthropology, biological anthropology, primatology, and neurobiology,” among others (Cosmides, Tooby, and Barkow, 1992, p. 4, pp. 23-24). These are not disciplines in which one becomes expert by behavioral mechanisms in a Swiss-army-knife mind. At least they and their readers must have quite broadly analytical and synoptic minds.
Cosmides must have believed this, speaking at that joint meeting of the Royal Society of London, dealing with the sciences, and the British Academy, dealing with arts, asking the audience to evaluate the model of a Swiss-army-knife mind. The mind is fully capable of evaluating any such behavioral modules, and of recommending appropriate education so as to reshape these dispositions in result. These psychologists seem to be quite able to re-adapt by critical thought their own adapted minds; nor is there any reason to think that they and their colleagues in evolutionary psychology are alone in this capacity. The capacity of Metanexus subscribers to read this posting seems quite non-modular.
The cumulation of a billion years of biological experimenting ends up, in the human species line, with individual humans with a hundred thousand or more genes, coding these discoveries. These genes make a brain with ten billion neurons, each with hundreds and sometimes thousands of possible synaptic connections, providing virtually endless opportunities for encoding ideas. These hookups begin to code cumulative cultural discoveries and to transmit them in new networks of information transfer (language and books, and, more recently, telephones, television, and computer internets). In evolutionary history, with the coming of humans, there appears the genesis of ideas; and in culture thereafter, ideas are perennially generated and regenerated. This phenomenon too has to be incorporated into any unified worldview.
Superposed on genetic endowments more or less common to all members of Homo sapiens, humans develop myriads of diverse cultures. They think their way through the world in amazingly diverse ways, from Druids to Albert Einstein. In computer imagery, the same “hardware” (biology) supports diverse programs of “software” (culture), even if there are many repeated subroutines.
The evolved brain allows many sets of mind. These ideas too “evolve” in the sense that they change and develop. Physics, for instance, has developed from Ptolemaic to Copernican theory. Biology has progressed from belief in the fixity of species to evolutionary theory. Ethics has rejected slavery and the unequal treatment of women, practices once widely accepted. Religion has progressed from polytheism to monotheism, or monism.
These are not claims about the evolution of the hardware that humans inherit natally; they are claims about the evolution of the software. Ideas are discovered and transmitted, and the mechanism of transmission is cultural. One does not have to have Plato’s genes to be a Platonist, Darwin’s genes to be a Darwinian, or Jesus’ genes to be a Christian. The thinkers responsible for shifting physics to a Copernican view, biology to a Darwinian view, and ethics to universal human rights were not from any particular racial or ethnic group. The system of inheritance of ideas is independent of the system of inheritance of genes. All this is pointing steadily to a difference in being human, to a complex mind indeed adapted for culture, that is, to a distinctive human genius.
Boyd, Robert, and Peter J. Richerson, 1985. Culture and the Evolutionary Process. Chicago: University of Chicago Press.
Buss, David, et al., 1990. “International Preferences in Selecting Mates: A Study of 37 Cultures,” Journal of Cross-Cultural Psychology 21:5-47.
Cosmides, Leda, John Tooby, and Jerome H. Barkow, 1992. “Introduction: Evolutionary Psychology and Conceptual Integration.” Pages 3-15 in Jerome H. Barkow, Leda Cosmides, and John Tooby, eds., The Adapted Mind: Evolutionary Psychology and the Generation of Culture. New York: Oxford University Press.
Dobzhansky, Theodosius, 1963. “Anthropology and the Natural Sciences–The Problem of Human Evolution,” Current Anthropology 4:138, 146-148.
Lumsden, Charles J., and Wilson, Edward O., 1981. Genes, Mind, and Culture. Cambridge, MA: Harvard University Press.
Plomin, Robert, 1990. “The Role of Inheritance in Behavior,” Science 248:183-188.
Tooby, John, and Leda Cosmides, 1992. “The Psychological Foundations of Culture.” Pages 19-136 in The Adapted Mind.
Washburn, S. L., 1978. “Animal Behavior and Social Anthropology.” Pages 53-74 in Michael S. Gregory, Anita Silvers, and Diane Sutch, eds., Sociobiology and Human Nature. San Francisco: Jossey-Bass Publishers.
Wilson, Edward O., 1978. On Human Nature. Cambridge, MA: Harvard University Press.