Terror Management Theory (Sheldon Solomon - Ernest Becker)

Wikipedia: 

"Terror management theory (TMT), in social psychology, states that human behavior is mostly motivated by the fear of mortality. According to TMT theorists, symbols that create cultural worldviews are fiercely protected as representations of actual life. The terror management theory posits that when people are reminded of their own deaths, they more readily enforce these symbols, often leading to punitive actions, violence, and war. Experiments conducted by Sheldon Solomon, Tom Pyszczynski, and Jeff Greenberg sought to lend evidence to the concept that mortality salience, or the awareness of one's own death, affects the decision making of groups and individuals."