The 2008 book "Nudge," coauthored by the scholars Cass Sunstein and Richard Thaler, made a splash by applying insights from behavioral economics to the realm of personal finance.
The main idea is that if individuals are given the right incentives, they'll make smarter choices with their money. One frequently cited example involves 401(k) enrollment. Lots of people never sign up for a retirement savings plan, even though it's in their own interest to do so. "Nudge" proposed a simple tweak offer 401(k)s on an opt-out basis, rather than opt-in in order to boost enrollment.