“Isn’t everyone like me?”: On the presence of self-similarity in strategic interactions

We propose that in strategic interactions a player is influenced by self-similarity. Self-similarity means that a player who chooses some action X tends to believe, to a greater extent than a player who chooses a different action, that other players will also choose action X. To demonstrate this phenomenon, we analyze the actions and the reported beliefs of players in a two-player two-action symmetric game. The game has the feature that for “materialistic” players, who wish to maximize their own payoff, there should be negative correlation between players’ actions and the beliefs that they assign to their opponent choosing the same action. We first elicit participants’ preferences over the outcomes of the game, and identify a large group of materialistic players. We then ask participants to choose an action in the game and report their beliefs. The reported beliefs of materialistic players are positively correlated with their actions, i.e., they are more likely to choose an action the stronger is their belief that their opponent will also choose the same action. We view this pattern as evidence for the presence of self-similarity.