Misery loves company: Social regret and social interaction effects in choices under risk and uncertainty

► We employ a series of controlled laboratory experiments to study the causes of peer effects in choice under uncertainty. ► We find strong peer group effects in the laboratory. Our design allows us to identify social interaction effects as the likely cause. ► We use a combination of theory and empirical analysis to show that preferences including “social regret” are more consistent with the data than preferences including a taste for conformity. ► We observe spillover effects, as observing anotherʼs choice of one risky gamble makes all risky gambles more likely to be chosen.