University of Minnesota
Psychology seems to be in the midst of an aperiodic swing between extreme forms of environmentalism and hereditarianism. More biological assumptions, variables, methods, and conclusions have crept into child development during the past 10 years than in the preceding 25. Although a welcome corrective, this trend toward psychobiology should be critically evaluated. We must first be alert to the dangers of reductionism inherent in biological explanations of behavioral phenomena. Second, we must avoid an extreme form of genetic determinism that ignores the necessary transactions between genotypes and their environments throughout the lifespan of development and ignores the important variations that exist among individuals. A serious appraisal of contemporary biology and genetics avoids both of these errors.
Explanations of behavioral phenomena may include variables derived from other levels of analysis, but their effects must be explained at a behavioral level. Genetic effects on behavior are plausible only as the explanation incorporates biochemical pathways to morphological characteristics (e.g., brain structures) that mediate the gene-behavior links. Even if current knowledge precludes a complete explanation, the partial understanding must incorporate hypothetical links from gene constituents to the behavioral level of organization. Genes do not act directly on behavior, and theoretical statements should not be reductionist in this sense.