If you think you know why you do things, you're probably wrong. Exploring how our unconscious determines our behavior, Alan goes into a magnetic resonance scanner in the Caltech lab of Steven Quartz to find out how his brain reacts to products both "cool" and "un-cool." Quartz and his associate Anette Asp are trying to find out why humans are obsessed with the social status of objects, and so are scanning the brains of people as they look at a range of products. Both Alan and Anette have brains that react strongly to things they find un-cool, as if they are recoiling from them. Steve, on the other hand, shows "shop-aholic" tendencies, his brain responding to cool objects not only in the region where his sense of self resides, but also in those regions controlling movement, as if he is reaching out to grab them. In the Harvard lab of Mahzarin Banaji, Alan takes a test designed to ferret out our unconscious prejudices. Called the Implicit Association Test, it measures the strength of associations we make without being aware of them. Alan, despite many years of working in feminist causes, still harbors a slight prejudice against associating women with a career. But the real surprise is that Mahzarin herself, despite a very successful career as a Harvard professor, shows a strong implicit bias against women in the workplace. Alan is presented with a tough moral choice by researcher Joshua Greene of Princeton: under what circumstance might he sacrifice the life of one person to save many? Greene's research suggests the emotional weight of the decision is critical, pitting the emotional centers of the brain against the rational ones.