Interactions Influence Emotional
Development in Rhesus Monkeys
Stephen J. Suomi
National Institutes of Health
The question of whether the characteristics that make us unique as individuals are largely determined by our heritage or shaped by our personal experiences has been debated since at least the time of Aristotle. Those who grew plants or raised animals practiced selective breeding long before anything was known about specific genes, and educators and philosophers alike asserted that “the child is the father of the man” centuries before any formulation of explicit theories of reinforcement by twentieth-century behaviorists. In recent years, we have heard claims by some behavioral geneticists that going shopping or getting a divorce is highly heritable, as well as arguments not about whether personality is determined by experience but whether the experience that really counts is with one's parents or with one's peers (e.g., Harris, 1998). Clearly, the nature-nurture debate is not new.
What has been relatively new among those who study development is an emerging realization that the basic questions underlying the nature-nurture debate over the years may have been largely misguided. Instead of arguing whether behavioral and biological characteristics that appear during development are genetic in origin or the product of specific experiences, these individuals acknowledge that both genetic and environmental factors can play crucial roles in shaping individual developmental trajectories. Behavioral geneticists, among others, have tried to determine the relative contributions of specific genetic and environmental factors