Counterfactual thoughts about what might have been ('if only…') are pervasive in everyday life. They are related to causal thoughts, they help people learn from experience and they influence diverse cognitive activities, from creativity to probability judgements. They give rise to emotions and social ascriptions such as guilt, regret and blame. People show remarkable regularities in the aspects of the past they mentally 'undo' in their counterfactual thoughts. These regularities provide clues about their mental representations and cognitive processes, such as keeping in mind true possibilities, and situations that are false but temporarily supposed to be true
