from completely heterosexual to completely homosexual. Kinsey reported that when the individuals' behavior, as well as their identity, are analyzed, a significant number of people appeared to be at least somewhat bisexual – i.e., they have some attraction to either sex, although usually one sex is preferred. Kinsey's methods have been criticized as flawed, particularly with regard to the randomness of his sample population, which included prison inmates, male prostitutes and those who willingly participated in discussion of previously taboo sexual topics. Nevertheless, Paul Gebhard, subsequent director of the Kinsey Institute for Sex Research, reexamined the data in the Kinsey Reports and concluded that removing the prison inmates and prostitutes barely affected the results. More recent researchers believe that Kinsey overestimated the rate of same-sex attraction because of flaws in his sampling methods. Social constructionism Because sexual orientation is complex, some academics and researchers, especially in queer studies, have argued that it is a historical and social construction. In 1976, philosopher and historian Michel Foucault argued in The History of Sexuality that homosexuality as an identity did not exist in the eighteenth century; that people instead spoke of "sodomy," which referred to sexual acts. Sodomy was a crime that was often ignored, but sometimes punished severely under sodomy laws. He wrote, "'Sexuality' is an invention of the modern state, the industrial revolution, and capitalism." Other scholars argue that there are significant continuities between ancient and modern homosexuality. The philosopher of science Michael Ruse has stated that the social constructionist approach, which is influenced by Foucault, is based on a selective reading of the historical record that confuses the existence of homosexual people with the way in which they are labelled or treated. In much of the modern world, sexual identity is defined based on the sex of one's partner. In some parts of the world, however, sexuality is often socially defined based on sexual roles, whether one is a penetrator or is penetrated. In Western cultures, people speak meaningfully of gay, lesbian, and bisexual identities and communities. In some other cultures, homosexuality and heterosexual labels do not emphasize an entire social identity or indicate community affiliation based on sexual orientation. Some historians and researchers argue that the emotional and affectionate activities associated with sexual-orientation terms such as "gay" and "heterosexual" change significantly over time and across cultural boundaries. For example, in many English-speaking nations, it is assumed that same-sex kissing,