The Nature Versus Nurture Debate

Few topics have wasted more emotional energy and created more futile academic fury than the question of behavioral plasticity. One extreme view holds that all animal behavior is instinctive, with little room for learning and flexibility of response. At the other extreme, some hold that behavior is modifiable over a great range of possibilities, and that individual experience determines behavior. Examples of both of these patterns can be found in animals, as well as intermediates at every step between. Knowing the balance between genetic constraints and phenotypic flexibility in animals is interesting and important, as this understanding gives great insight into how evolutionary forces shape behavior.

The ³nature² school of thought came to the forefront in the early to mid 20th century among European ethologists, such as Konrad Lorenz. Their studies emphasized the roles of instinct, fixed patterns of behavior, and the influence of evolution on behavior.

The ³nurture² school of thought was championed by American psychologists, who, starting with simple models of learning, such as conditioning, argued that behavior is learned, modifiable due to experience, and not, at least in humans, constrained by evolutionary history.

Applying the nature/nurture question to human behavior nearly always generates trouble. Data interpreted to show genetic bases for differences among humans in intelligence, motor learning capabilities, criminality, and a broad range of other behaviors has, unfortunately, been used to support racism and other forms of bigotry. Because science is a stepwise progression of improvements of methods, scientists often avoid conclusions which may have harmful sociological or political effects on groups of people.

Sociobiology provided a major arena for the nature/nurture debate in the 1970¹s and 1980¹s. This discipline, championed by E. O. Wilson, integrates thought from ethology, ecology, evolution, and genetics in an attempt to develop a deeper understanding of the evolution of behavior. While this approach attracts many behavioral biologists, detractors, such as R. C. Lewontin, suspect that sociobiology (genetic determinism) ultimately supports racist or class-based justifications for inequities in human societies. This vituperative argument has ranged far outside the boundaries of science.

An example of a recent nature/nurture debate is the argument caused by R. Thornhill¹s argument that rape is an adaptive reproductive strategy in humans. This assertion challenges the notion that sex criminals can be rehabilitated. Some people think it raises the possibility that potential sex criminals could be genetically identified and segregated from society. These assertions are abhorrent to those who think that human behavior is shaped by experience and that all humans are capable of improvement and rehabilitation. Regardless of whether you agree with Thornhill or his critics, you should easily understand how volatile this question has become.

Hellman, Hal, 1998. Great feuds in science : ten of the liveliest disputes ever. New York : Wiley

Lewontin, R.C., S. Rose, and L. J. Kamin. 1984. Not in our genes : biology, ideology, and human nature New York : Pantheon Books

Segerstråle, Ullica Christina Olofsdotter. 2000. Defenders of the truth : the battle for science in the sociobiology debate and beyond Oxford ; New York : Oxford University Press.

Shockley, W. 1992. Shockley on eugenics and race : the application of science to the solution of human problems / preface by Arthur R. Jensen ; Roger Pearson [editor] Washington, D.C. : Scott-Townsend Publishers

Thornhill, R., Palmer, C T., Coyne, Jerry A., Berry, Andrew. 2000. A natural history of rape: biological bases of sexual coercion. Nature. 404: 121

Wilson, E. O. 1975. Sociobiology : the new synthesis Cambridge, Mass. : Belknap Press of Harvard University Press