A Check for Rational Inattention

Who is rationally inattentive, and in what situations? Models of rational inattention allow agents to make mistakes in their actions but assume the agents optimize their allocation of attention. Using millions of online chess moves, I test this assumption by comparing the marginal benefits (better moves) and marginal costs (less time for future moves) of attention. I find that high-skilled players equalize marginal benefit and cost, but low-skilled players have higher marginal cost (i.e., they spend too long on moves). I also find that having less time leads to deviations from rational inattention. A simple intervention improves players’ attention allocation.