When we get near money, our decision-making processes often go haywire. It's like placing a compass next to a magnet-we can't figure out which direction is north, and our finances can head south as a result.

Within the growing academic field of behavioral finance, researchers are discovering just how easily we are swayed by subtle emotional forces, no matter how hard we try to make rational choices. Do you hate losing a hundred dollars more than you love receiving a hundred dollars? Are you reluctant to make an investment if the people around you aren't doing so? These kinds of...