Omission bias

Omission bias arises from the difference in perceived responsibility and moral agency attributed to actions versus inactions. When someone commits a harmful act, they are directly responsible and visibly involved in the outcome, triggering stronger emotional responses. In contrast, omissions often go unnoticed or unpunished, as the actor appears passive and detached from the negative consequence, fostering the belief that inaction is less blameworthy. The bias is reinforced by cognitive tendencies, such as memory and repetition, where actions tend to be more salient and memorable than inactions.

• In a medical context, a physician might perceive administering a treatment with a small risk of side effects as worse than withholding it, even if the patient suffers as a result.
• In sports, a referee might be more criticized for making a wrong call than for failing to notice a foul.
• In everyday decision-making, someone might be judged more harshly for initiating a confrontation rather than avoiding one, even if avoiding leads to greater harm.

Some critics argue that omission bias may not necessarily reflect a cognitive bias but rather a rational preference for non-interference over intervention, based on cultural or moral values that prioritize individual autonomy and caution. Additionally, others suggest that in many real-world scenarios, differentiating between action and inaction is complex, and the context often dictates the perceived moral weight of an individual's choices.