Humans define the groups to which they belong in abstract terms. Often they strive for lasting emotional bonding with anonymous others and make their greatest exertions in killing and dying--not to preserve their own lives or to defend their families and friends--but for the sake of an idea: the transcendent moral conception of “who we are.”

This is the "privilege of absurdity; to which no living creature is subject, but man only of which Hobbes wrote in The Descent of Man.

Across cultures, primary group identity is bounded by sacred values in the form of religious beliefs or transcendental ideologies. Whether for cooperation or conflict, sacred values, like devotion to God or a collective cause, signal group identity and operate as moral imperatives that inspire non-rational exertions independent of likely outcomes.

In interviews, experiments, and surveys with Palestinians, Israelis, Indonesians, Indians, Afghans, and Iranians, my research with psychologists Jeremy Ginges and Douglas Medin finds that offering people material incentives (large amounts of money, guarantees for a life free of political violence) to compromise sacred values can backfire, increasing stated willingness to use violence toward compromise.