An eye-tracking study of feature-based choice in one-shot games

Previous experimental research suggests that individuals apply rules of thumb to a simplified mental model of the "real'' decision problem. We claim that this simplification is obtained either by neglecting the other players' incentives and beliefs or by taking them into consideration only for a subset of game outcomes. We analyze subjects' eye movements while playing a series of two-person, 3 9 3 one-shot games in normal form. Games within each class differ by a set of descriptive features (i.e., features that can be changed without altering the game equilibrium properties). Data show that subjects on average perform partial or non-strategic analysis of the payoff matrix, often ignoring the opponent's payoffs and rarely performing the necessary steps to detect dominance. Our analysis of eye-movements supports the hypothesis that subjects use simple decision rules such as "choose the strategy with the highest average payoff'' or "choose the strategy leading to an attractive and symmetric outcome'' without (optimally) incorporating knowledge on the opponent's behavior. Lookup patterns resulted being feature and game invariant, heterogeneous across subjects, but stable within subjects. Using a cluster analysis, we find correlations between eye-movements and choices; however, applying the Cognitive Hierarchy model to our data, we show that only some of the subjects present both information search patterns and choices compatible with a specific cognitive level. We also find a series of correlations between strategic behavior and individual characteristics like risk attitude, short-term memory capacity, and mathematical and logical abilities.