According to violation–compensation models of cognitive conflict, experiences that violate expected associations evoke a common, biologically based syndrome of aversive arousal, which in turn motivates compensation efforts to relieve this arousal. However, while substantial research shows that people indeed respond with increased arousal to expectancy violating events, evidence for the motivating role of arousal is rarely found. In two within-subjects studies (N = 44 and N = 50), we demonstrate evidence for the motivating role of arousal in this violation–compensation process among university students. Using pupillometry and the hindsight bias phenomenon, we show that people respond with greater arousal when presented with expectancy violating information. In turn, we show that the pupillary response is positively related to the amount of hindsight bias being displayed. These findings provide further insights into the process underlying the hindsight bias and, crucially, support key predictions following from threat–compensation models.