Abstract: Deliberating groups, including juries, typically end up in a more extreme position in line with their predeliberation tendencies. A jury whose members are inclined, before deliberation, to find a defendant not guilty will likely render a verdict of not guilty; a jury whose members want to award punitive damages will likely produce an award higher than that of the median juror. The phenomenon of group polarization, found in many domains, stems from a combination of information pooling and peer pressure. The events portrayed in the film 12 Angry Men seem to defy the logic of group polarization, but the film nonetheless shows an acute psychological sense.