Abstract

The side-effect effect is the seemingly irrational tendency for people to say harmful side effects were more intentional than helpful side effects of the same action. But the tendency may not be irrational. According to the Tradeoffs Justification Model, judgments of a person's intentions to cause harm depend on how that person decided to act, and on whether the reasons for acting justified causing the harmful consequences. Across three experiments (N = 660), unjustified harms were viewed as more intentional than justified harms. If the person had a choice of what to do and knowingly caused harm for no good reason, people judged that the person must have actually desired and intended to cause the harm. However, if the person had a strong, compelling reason (e.g., to ransom his daughter from kidnappers) that the observer deemed to have justified causing the harm, then observers thought the harm was weakly intended at most. Taboo harms that violated sacred moral values were especially likely to be seen as intentional because most reasons do not adequately justify violating a sacred value.