What we regret most are lost opportunities: a theory of regret intensity.

A recent theory (Roese & Summerville, 2005) has suggested that regret is intensified by perceptions of future opportunity. In this work, however, it is proposed that feelings of regret are more likely elicited by perceptions of lost opportunity: People regret outcomes that could have been changed in the past but can no longer be changed and for which people experience low psychological closure. Consistent with the lost opportunity principle, Study 1 revealed that regretted experiences in the most commonly regretted life domains are perceived as offering the least opportunity for improvement in the future, Study 2 indicated that people experience the most regret for outcomes that are not repeatable, and Study 3 revealed that perceptions of higher past than future opportunities and low psychological closure predict regret intensity. Discussion focuses on the hope-inducing yet ephemeral nature of perceived future opportunity and on the relationship between dissonance reduction and closure.