Paul Zak: Trust, morality -- and oxytocin. Philip Zimbardo shows how people become monsters ... or heroes. Tim Ferriss: Smash fear, learn anything. Dan Gilbert asks, Why are we happy? Beau Lotto: Optical illusions show how we see. David Gallo shows underwater astonishments.
John Hodgman: Aliens, love -- where are they? Rives on 4 a.m. Michael Shermer on strange beliefs.