Exceptionality effect is the phenomenon that people associate stronger negative affect with a negative outcome when it is a result of an exception (abnormal behaviour) compared to when it is a result of routine (normal behaviour). In this pre-registered meta-analysis, we examined exceptionality effect in 48 studies (N = 4212). An analysis of 35 experimental studies (n = 3332) showed medium to strong effect (g = 0.60, 95% confidence intervals (CI) [0.41, 0.79]) for past behaviour across several measures (regret/affect: g = 0.66, counterfactual thought: g = 0.39, self-blame: g = 0.44, victim compensation: g = 0.39, offender punishment: g = 0.51). An analysis of 13 one-sample studies presenting a comparison of exceptional and routine behaviours simultaneously (n = 1217) revealed a very strong exceptionality effect (converted g = 1.98, CI [1.57, 2.38]). We tested several theoretical moderators: norm strength, event controllability, outcome rarity, action versus inaction, and status quo. We found that exceptionality effect was stronger when the routine was aligned with the status quo option and with action rather than for inaction. All materials are available on: https://osf.io/542c7/.
Keywords: Norm theory; exception routine; exceptionality effect; meta-analysis; normality; past behaviour; regret.