Bias toward the status quo, found in choice and in emotional reactions to adverse outcomes, has been confounded with bias toward omission. We unconfounded these effects with scenarios in which change occurs unless action is taken. Subjects reacted more strongly to adverse outcomes caused by action, whether the status quo was maintained or not, and subjects preferred inaction over action even when inaction was associated with change. No status-quo bias was found in a matching task, which did not require action. The observed status-quo bias is at least partly caused by a bias toward omissions.