How does reasoning influence intentionality attribution in the case of side effects?

To evaluate others’ actions objectively, one must integrate the actor’s mental states with the potential consequences of his actions. However, consequences can distort the perception of intentionality. The Knobe effect, or “side-effect effect,” demonstrates that individuals attribute greater intentionality to negative than positive foreseen yet unintended side effects. This study explores how reasoning styles and abilities influence these judgments. A sample of 172 college students completed validated reasoning style questionnaires, including the Rational-Experiential Inventory (REI) and the Actively Open-Minded Thinking scale (AOT), a syllogistic reasoning task, and scenario-based tasks in a randomized, between-subjects design (negative vs. positive side effect). Our findings reveal that a more deliberative reasoning style and longer response times both reduce bias in attributing intentionality to negative side effects, highlighting two distinct pathways through which response times mediate the influence of reasoning style on reducing biased judgments. We explore how reasoning affects our attributions of intentionality leading to a more balanced consideration of an actor’s mental state and the consequences in moral judgment.