We conduct a study in which subjects trade stocks in an experimental market while we measure their brain activity using functional magnetic resonance imaging. All of the subjects trade in a suboptimal way. We use the neural data to test a “realization utility” explanation for their behavior....

The "disposition effect" is the tendency to sell assets that have gained value ("winners") and keep assets that have lost value ("losers"). Disposition effects can be explained by two elements of prospect theory: The idea that people value gains and losses relative to the initial purchase price...

We use measures of neural activity provided by functional magnetic resonance imaging (fMRI) to test the "realization utility" theory of investor behavior, which posits that people derive utility directly from the act of realizing gains and losses. Subjects traded stocks in an experimental market...

The studies were designed to test whether active naturally-occurring markets could be manipulated experimentally in a way that permitted statistically powerful identification of whether manipulation generally works (rather than anecdotal evidence). The studies also serve as a reminder that true...