Terror management theory proposes that human behavior and culture are strongly influenced by an innate psychological fear of death. The theory suggests that culture and self-esteem serve to help people deny or manage the terror of realizing their own mortality. When reminded of death, people tend to more strongly defend their own cultural beliefs and worldviews and reject those who are different. The theory is supported by research showing that mortality salience increases in-group favoritism and out-group aggression. However, some criticisms argue that the theory's claims are not well supported by evidence and its assumptions do not necessarily increase survival.