Cultivation theory was first advanced by professor George Gerbner in the 1960s; it was later expanded upon by Gerbner and Larry Gross. Cultivation theory began as a way to test the impact of television on viewers, especially how exposure to violence through television affects human beings. The theory's key proposition is that "the more time people spend 'living' in the television world, the more likely they are to believe social reality aligns with reality portrayed on television." Because cultivation theory assumes the existence of objective reality and value-neutral research, it can be categorized as part of positivistic philosophy.