A new paper reviews how psychology, biology, and neurology are ganging up on economics to prove that, when it comes to making decisions, people are anything but rational. The old economic theory of consumers says that "people should relish choice." And we do. Shopping can be fun, democracy is better than its alternatives, and a diverse and fully stocked grocery store ice cream freezer is quite nearly the closest thing to heaven on earth. But other fields of science tell a more complicated story. First, making a choice is physically exhausting, literally, so that somebody forced to make a number of decisions in a row is likely to get lazy and dumb. (That's one reason why stores place candy near the check-out aisle: They suspect your brain is too zonked to resist.) Second, having too many choices can make us less likely to come to a conclusion. In a famous study of the so-called "paradox of choice", psychologists Mark Lepper and Sheena Iyengar found that customers presented with six jam varieties were more likely to buy one than customers offered a choice of 24.