A paradox: The triumph of hereditarian and environmental explanations

When there are competing explanations for a set of phenomena, one of two outcomes can generally be anticipated. Either evidence steadily accrues in favor of one side of the argument; in such a case, the competing position (e.g., phlogiston or Lamarckianism) is gradually abandoned or radically reformulated. Or it is determined that neither side of the debate will triumph, either because the contrasting case proves too difficult to refute, or because the apparently conflicting issues have been improperly formulated.

In the behavioral sciences, no issue has been more passionately joined than the relative contribution to human behavior of hereditary (genetic) or environmental (cultural) approaches. In one sense, the debate dates back at least to the beginnings of the modern philosophical era: Contemporary hereditarians (hereafter Hs) can date back their pedigree to Descartes and Leibnitz, while contemporary environmentalists (hereafter Es) can trace their intellectual heritage to the British empiricists, such as Locke and Hume.

In the past century, since the times of the evolutionary theorist Charles Darwin and the pioneering geneticist Gregor Mendel, the issue has been joined with ever greater sharpness, even as the pendulum has continued to swing between the rival positions. For the first several decades of the behavioral sciences, the view held sway that humans were hostages to their biological heritage. Then, with the advent of the Behaviorist and Learning Theory approaches, the contributions of the environment were reciprocally stressed.