Templeton is holding a forum on whether whether moral action depends upon reasoning. Jonah Lehrer responds by looking at the brains of pyschopaths. He contends that reason is relevant but that the emotional core of our brains is key to morality:
Neuroscientists are beginning to identify the specific deficits that define the psychopathic brain. The main problem seems to be a broken amygdala, a brain area responsible for secreting aversive emotions, like fear and anxiety. As a result, psychopaths never feel bad when they make other people feel bad. Aggression doesn't make them nervous. Terror isn't terrifying. (Brain imaging studies have demonstrated that the amygdala is activated when most people even think about committing a "moral transgression.")
This emotional void means that psychopaths never learn from their adverse experiences: They are four times as likely as other prisoners to commit another crime after being released. For a psychopath on parole, there is nothing inherently wrong with violence. Hurting someone else is just another way of getting what they want, a perfectly reasonable way to satisfy their desires. In other words, it is the absence of emotion--and not a lack of rationality--that makes the most basic moral concepts incomprehensible to them.