sociobiology, controversial field that studies how natural selection, previously used only to explain the evolution of physical characteristics, shapes behavior in animals and humans. The theory has contributed to the understanding of certain evolutionary traits in the animal world, such as how instinctive parental behaviors of animals are determined in part by the need to ensure survival of offspring. A related aspect of sociobiology deals with altruistic behaviors in general. In a theory called kin selection, animals that behave altruistically would have their genes passed on by helping relatives who share their genes survive to reproduce, just as they would by producing offspring of their own.
The theory first gained attention when E. O. Wilson of Harvard published Sociobiology (1975); it became controversial when he proposed extending the theory to explain human social behavior and psychological patterns. Critics charged that this application of sociobiology was a form of genetic determinism and that it failed to take into account the complexity of human behavior and the impact of the environment on human development.
Scientists have recently discovered individual genes in laboratory worms that influence social behavior, such as gregarious feeding habits. Continued research of this kind, into what has been called the "molecular biology of social behavior," is likely to provide new insights into sociobiology.