Eyewitness memory for emotionally arousing events
For three decades, psychologists and forensic practitioners have been asking, “How does emotional arousal affect eyewitness memory?” Despite much research, a definite and comprehensive answer to this question has not been forthcoming. This thesis investigates some of the pertinent issues regarding the nature of the effects on memory (enhancements, impairments), the aspects of memory affected (completeness vis. Accuracy, recall vs. identifications, central vs. peripheral details), and the underlying mechanisms (selective cognitive processing including post-stimulus elaboration), employing empirical designs that are both novel and more ecologically valid than seen in previous research. Experiment 1 demonstrated the difficulties in studying the effects on memory as a function of the individual level of arousal experienced by participants during a live staged crime event. Therefore, the three experiments that followed compared memory for details from emotionally arousing vs. less or non-arousing events via dynamic videos and an interactive simulator. These experiments revealed that recall accuracy is often enhanced for event details central to the source of arousal. However, Experiments 2 and 3 demonstrated that the completeness of recall, particularly for event details preceding an arousal criminal act, tends to be impaired. Experiment 4 qualified the latter finding by demonstrating that impairments are not an inevitable consequence of arousal per se, nor is the activation of cognitive mechanism such as post-stimulus elaboration, but rather a consequence of the way in which arousal is induced (i.e. through the sight of weapons vs. through empathy and involvement in an unfolding plot). Lastly, recall for and identification of crime perpetrators were largely unaffected by emotional arousal.