When personality meets surprise: individual differences in memory for unexpected events.

Introduction: Expectation shapes memory formation, with unexpected stimuli typically eliciting richer encoding, greater associative processing, and superior recollection. Yet, the role of personality traits in modulating this effect is poorly understood, despite their potential influence on how individuals engage with and interpret environmental cues. This study investigated whether dispositional factors shape memory encoding for expected versus unexpected events. Methods: Across two experiments, participants learned symbol-stimulus contingencies that were later violated for a subset of stimuli at encoding, followed by a recognition memory test. Additionally, in Experiment 1 (n = 55), state/trait anxiety and risk-taking were measured, while in Experiment 2 (n = 142), participants completed the Big Five personality inventory. Results: In both experiments, unexpected events boosted subsequent recollection, but the magnitude of this benefit varied systematically with individual differences. Experiment 1 showed that individuals low in trait anxiety and risk-taking exhibited pronounced recollection benefits for unexpected events, an advantage that diminished in highly anxious or risk-taking individuals. Experiment 2 extended these findings, revealing that low extraversion and high negative emotionality attenuated the recollection advantage of unexpected events. Discussion: These findings demonstrate that personality traits dynamically shape how expectation guides memory formation and offer new insight into the interplay between dispositional factors and cognition. They also highlight important implications for both memory theory and applied contexts.