From The Economist:
The role of emotions in decisions makes perfect sense. For situations met frequently in the past, such as obtaining food and mates, and confronting or fleeing from threats, the neural mechanisms required to weigh up the pros and cons will have been honed by evolution to produce an optimal outcome. Since emotion is the mechanism by which animals are prodded towards such outcomes, evolutionary and economic theory predict the same practical consequences for utility in these cases. But does this still apply when the ancestral machinery has to respond to the stimuli of urban modernity?
One of the people who thinks that it does not is George Loewenstein, an economist at Carnegie Mellon University, in Pittsburgh. In particular, he suspects that modern shopping has subverted the decision-making machinery in a way that encourages people to run up debt. To prove the point he has teamed up with two psychologists, Brian Knutson of Stanford University and Drazen Prelec of the Massachusetts Institute of Technology, to look at what happens in the brain when it is deciding what to buy.