Jonathan Haidt, of the University of Virginia, has shown how viscera and emotion often drive our decisionmaking, with conscious cognition mopping up afterward, trying to come up with rationalizations for that gut decision. The viscera that can influence moral decisionmaking and the brain’s confusion about the literalness of symbols can have enormous consequences. Part of the emotional contagion of the genocide of Tutsis in Rwanda arose from the fact that when militant Hutu propagandists called for the eradication of the Tutsi, they iconically referred to them as “cockroaches.” Get someone to the point where his insula activates at the mention of an entire people, and he’s primed to join the bloodletting.