Robert Ludlow "Bob" Trivers (/ˈtrɪvərz/; born February 19, 1943) is an American evolutionary biologist and sociobiologist, who is a Professor of Anthropology and Biological Sciences at Rutgers University. Trivers proposed the theories of reciprocal altruism (1971), parental investment (1972), facultative sex ratio determination (1973), and parent–offspring conflict (1974). He has also contributed by explaining self-deception as an adaptive evolutionary strategy (first described in 1976) and discussing intragenomic conflict.