Freakonomics holds the view that people respond to incentives, perhaps in undesirable ways, but always rationally. Dan Ariely demonstrates that people are deeply irrational and this is predictable.

Dan Ariely is the bestselling author of "Predictably Irrational," "The Upside of Irrationality," and "The (Honest) Truth About Dishonesty." He is the James B. Duke Professor of Psychology and Behavioral Economics at Duke University and the founder of the Center for Advanced Hindsight. His work has been featured in various publications. He lives with his family in North Carolina.

Why do our headaches persist after taking a one-cent aspirin but disappear when we take a fifth?.