To understand my decisions, you must understand my task: Expertise effects in theory of mind.

Human behavior is frequently constrained by the behavior of other agents (increasingly artificial agents like machines and software). In a cooperative setting, each individual needs to understand the partners' intentions and corresponding actions to plan their actions adequately. Misunderstandings have adverse effects and diminish the efficiency of cooperation. We created a game-based experiment to study the effects of understanding a partner's actions in a cooperative setting. In this game, the players depend on each other's ability to make good decisions to succeed. In two studies (N = 87, N = 281), we collected data on the understanding of an artificial agent, operationalized as the ability to predict its actions and the skill at the task itself. The participants improve at predicting the agent's actions and at their subtasks in the game over time. Following an incorrect prediction, the participants' performance on their subtask was worse, as measured by the' quality, speed, and efficiency of their actions. Results of Study 2 suggest that the improvements in predicting the agent's actions are likely the result of an improved understanding of the game rather than an improved understanding of the agent.