Adults and Children Engage in Subtle and Fine-Grained Action Interpretation and Evaluation in Moral Dilemmas

Understanding the actions of others is fundamental for human social life. It builds on a grasp of the subjective intentionality behind behavior: one action comprises different things simultaneously (e.g., moving their arm, turning on the light) but which of these constitute intentional actions, in contrast to merely foreseen side-effects (e.g., increasing the electricity bill), depends on the description under which the agent represents the acts. She may be acting intentionally only under the description "turning on the light," but did not turn on the light in order to increase the electricity bill. In preregistered studies (N = 620), we asked how adults and children engage in such complex subjective action interpretation and evaluation in moral dilemmas. To capture the deep structure of subjects' representations of the intentional structures of actions, we derived "act trees" from their response patterns to questions about the acts. Results suggest that people systematically distinguish between intended main and merely foreseen side-effects in their moral and intentionality judgments, even when main and side-effects were closely related and the latter were harmful. Additional experimental conditions suggest that, when given ambiguous information, the majority of subjects assume that agents act with beneficial main intentions. This "good intention prior" was so strong that participants attributed good intentions even when the harmful action was no longer necessary to resolve the dilemma (Study 2). These methods provide promising new ways to investigate in more subtle and fine-grained ways how reasoners parse, interpret, and evaluate complex actions.