Gain attraction in the presence of social interactions

The purpose of this paper is to suggest that a fundamental cause of market booms and busts is that investor risk attitudes change during market booms. Specifically, the authors propose that an investor’s risk aversion falls as (s)he attempts to “keep up with the Joneses.” This paper studies changing risk attitudes induced by social interactions, and shows that risk-seeking behavior that is initially successful may induce copycat behavior and lead individuals in the same peer group to reduce their degree of risk aversion to attempt to obtain similar rewards, a phenomenon we call “Gain attraction in the presence of social interactions.”

The authors propose a new theoretical model that incorporates the social interaction term into the value function of prospect theory. The modified value function empowers the standard prospect theory by introducing the idea that people often compare themselves to others and then compare their gains to the gains of others. The model predicts that, if people exhibit some degree of envy, they will treat the observed utility achieved by others as destination points and will reposition themselves to the new reference points, and at that point their willingness to accept risk dramatically increases.

The theoretical model is tested empirically against experimental data and survey data. Consistent with the theoretical prediction, the experimental results suggest that, after subjects observed the behavior of the leading investor in the controlled laboratory condition, there was a significant increase in risk-taking behavior. The survey results further confirm that envy is an emotional force behind the dissatisfaction and disappointment among investors when they miss available opportunities that others were able to take advantage of.

This study provides evidence that investment decisions are not made in a social vacuum by isolated individuals, but rather in social settings in which individuals are influenced by the actions and outcomes of their peers. The study also opens up a new research avenue that the reduction in risk aversion induced by peer effects may be an important element explaining how greed is transmitted across the economy during times of financial boom, thus helping to fuel the flames of financial crises.