“Nature versus nurture” is the popular phrase depicting the debate between proponents of sociobiology (biological or genetic determinism) and proponents of behaviorism (social determinism) over the reasons adult humans come to behave the way they do.
II. Genetic Markers
III. Society and Social “Types”
In his 1930 classic Behaviorism, John B. Watson (1878–1958), father of behavioral psychology, wrote perhaps the strongest formulation of a view of nurture, with development through learning and environment represented as the determinant of human possibilities. He said, “Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I’ll guarantee to take any one at random and train him to become any type of specialist I might select— doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors.”
In opposition to such sentiments, especially after the foundations of inheritance changed with the discovery of DNA, other scientists looked for physical rather than social explanations for human characteristics and achievements. Sociobiology (biological or genetic determinism) is a field in which human behaviors are studied to clarify how they might emerge from evolutionary mechanisms. For example, altruism (in which an individual sacrifices for a greater good at the expense of his or her own genetic success) may be explained as advancing the genetic fitness of a group. Specifically, one’s genes are often shared with relatives; therefore if a behavior advances the evolutionary success of the larger group, the genes are propagated even if not by a specific individual. Other behaviors then are considered based on similar assessments of individual and group fitness and thus the ability to pass on genes to subsequent generations.
Sociobiology rests on ideas about genetic determinism, a theory that attempts to link complex behaviors to genes at more individual levels. Attempts have been made to connect alcoholism, homosexuality, mental illness, and many other behaviors and conditions to specific genetic mechanisms. Despite occasional features in the popular media, however, careful scrutiny of genetic attributions rarely hold up; either the statistical measures are re-examined and dismissed by other scholars or (more frequently) dismissed when a broader population is sampled inconclusively for a specific genetic marker.
Despite current problems, certain genetic diseases are still good models for genetic determinism. For example, Huntington’s disease is a heritable neurological illness marked by loss of motor control and physical and psychological decline. It is unambiguously linked to a kind of mutation (a repeated amino acid sequence) on chromosome four. Even that mutation has variations in the number of repeated sequences, and the severity and progression of the disease is strongly, though not exactly, linked to the scope of the mutation. Similarly, although BRCA1 and BRCA2 (breast cancer 1 and 2, early onset) genes are statistically linked to increased risk of breast cancer in women, the detection of either gene in any particular woman does not necessarily mean that she will definitely develop breast cancer. This leads to a great deal of uncertainty and anxiety for women who carry these genes because they have to consider preventive treatments such as drugs, which have serious side effects, or even removal of the breasts to try to avoid cancer. It is further complicated by the fact that many breast cancers are not linked to the BRCA markers, meaning that being screened negatively for these markers does not guarantee that any woman so screened will not eventually develop breast cancer. Thus, for many diseases, such as breast cancer, such a focus on genetics is sometimes seen as a distraction from research on environmental contributions—such as exposure to toxins or dietary factors that might cause breast cancer—because it focuses attention on cure rather than prevention.
Although the popular appeal of genetic determinism is hard to counteract, the attribution of apparently straightforward medical conditions to genetic inheritance leads to a critique of “nature” by the proponents of social determinism. Twin studies, for example, are taken to “prove” the heritability of many things, from weight and height to spirituality or political affiliation. One of the most important factors, probability, is rarely considered. Suppose, for example, that a researcher found that twins who were separated at birth and now live 150 miles apart in Iowa both drove red pickup trucks and liked a particular brand of beer and hot dogs. He might see these facts as proof that the observed behaviors were caused by genes. However, one must also sort out the probability of any two adult men driving red trucks and liking particular brands of beer and hot dogs. In Iowa, that may not be a very surprising correlation. If one of our twins had been raised in Ireland rather than Iowa, nearer his twin, and liked a particular beer (rather than stout) and hot dogs (rather than haggis) and drove a red pickup truck, then that might be a more interesting finding. That is, environments are often assumed to be completely dissimilar, neglecting the facts of broadly shared culture and parenting practices. There are no systematic or agreed-upon measures of “environment” in twin studies; therefore so results are necessarily inconclusive.
It is clear that genetic theories of characteristics such as intelligence or athletic ability can easily be associated with racism and eugenics and can have complicated political and social justice implications. Stereotypes such as “white men can’t jump” or “blacks can’t do math” become taken as facts rather than as phenomena that may or may not be true or that may have social explanations ranging from the demographic to the psychological. For example, if people believed that white people cannot jump, white people might not put themselves in situations where they would have a chance to improve their jumping, thus creating a self-fulfilling prophecy that is only superficially true, and so on.
Society and Social “Types”
Social determinist explanations also have their racist counterparts, however. Stereotypes about “the black family” are an environmental, rather than genetic, explanations of the dynamics of urban black poverty. Adopting a view that something such as homosexuality is a product of nature (genes in contemporary theories) can be an attempt to argue that because it is not chosen and is a natural part of human existence, it therefore should not be subject to discrimination. A theory of homosexuality as genetic, however, does not prevent people from discriminating: skin color is natural, and yet people still use it as a basis for discrimination. Thus a genetic theory does not prevent continued pathologization, and a search for “treatments” or “cures” may in fact enhance efforts to try to eliminate a behavior or kind of person. Although theories about nurture or the social construction of behavior and identity are often interpreted as more socially progressive, they are also not immune to producing justifications for discrimination or medical intervention.
In addition to ambiguous political outcomes, theories of nature or nurture both share a tendency toward a fundamental attribution error or typological thinking. That is, a behavior is extrapolated to be an expression of the “true self” or of a “type” of person distinct from other types. For example, there is little correlation between whether or not people keep their rooms neat and also turn in neat homework. Yet most people will examine either the state of the room or the homework and infer that the one matches the other. In terms of human behaviors such as homosexuality, many persons engage in same-sex behaviors yet do not self-identify as homosexual. Not only can sexual orientation change across the life course but, in addition, the context (ranging from the local, such as prisons, to the historical, such as Sparta in Ancient Greece) shapes the meaning, frequency, and persistence of the behavior. These things greatly complicate the attribution of either a genetic foundation or an environmental “cause” that holds across time or context.
In an obvious sense, nature matters: children generally look like their biological parents, and populations of people do have common features, whether facial features, skin color, or tendencies toward risk factors in illnesses. But because genes require expression to have their effects, it is impossible to separate nature and nurture in any meaningful sense. Th eories such as dynamic systems theory are proposed to explain the complexity of human development, considering both the genetic and biological features and their interaction within environmental contexts. For example, many genes contribute to height, but the expression of those genes is strongly influenced by nutrition and exercise.
There is no way to completely untangle the multiple factors affecting human characteristics and behavior except in the broadest statistical sense, which makes it extremely difficult to infer anything about a specific individual. Both researchers and the lay public, however, will continue to try to single out either nature or nurture as determining factors for behavior, illness, and identity because these theories support important political narratives and projects that shape the distribution of goods, services, and social justice in contemporary culture.
- Fausto-Sterling, Anne, Sexing the Body. New York: Basic Books, 2000.
- Gillette, Aaron, Eugenics and the Nature-Nurture Debate in the Twentieth Century. New York: Palgrave Macmillan, 2007.
- Parens, Erik, et al., eds., Wrestling with Behavioral Genetics: Science, Ethics, and Public Conversation. Baltimore: Johns Hopkins University Press, 2006.
- Ridley, Matt, Nature via Nurture: Genes, Experience, and What Makes Us Human. New York: HarperCollins, 2003.
- Watson, John B., Behaviorism, rev. ed. Chicago: University of Chicago Press, 1958.
- Wilson, E. O. Sociobiology: The New Synthesis, 25th anniversary ed. Cambridge, MA: Belknap/ Harvard University Press, 2000.
- Wright, Lawrence, Twins: And What They Tell Us about Who We Are. New York: Wiley, 1997.