Later published in Cynthia Garcia Coll ed. Nature and Nurture: The Complex Interplay of Genetic and Environmental Influences on Human Behavior and Development, Erlbaum 2003.
Birds do not need to be taught how to build nests. Evidently the behavior is largely instinctual. Humans need to be taught nearly everything they do (or at least need to learn through imitation). Further, our experience of our own behavior is that we make conscious choices – that we are the masters of our own ships. It thus comes as a shock to many people that genetic differences have been shown to be an important determinant of variation in a wide range of human behaviors.
Besides a number of psycho-pathologies, a large and growing list of behaviors— including major measurable aspects of personality (Loehlin 1992), political conservatism (Eaves et. al. 1997), religiosity (Waller et. al. 1990), occupational attitudes (Lykken et. al. 1993), social attitudes (Martin et. al. 1986), marital status (Trumbetta et. al. submitted), and even television watching (Plomin et. al. 1990)—have all been shown to be heritable.