Recent Research: Effects of Stress on Police and Citizen Eyewitness Recall
Zimmerman, Laura A., Canadian Journal of Police and Security Services
Stanny, C. J. & Johnson, T. C. (2000). Effects of stress induced by a simulated shooting on recall by police and citizen witnesses. American Journal of Psychology, 113(3), 359-386.
Research indicates that stress experienced by eyewitnesses during criminal events may be detrimental to later recollection of those events (c.f. Narby, Cutler, & Penrod, 1996), but it may be argued that these levels of stress may vary depending on who the witness is. Police officers make up one population of eyewitnesses who frequently encounter criminal activity and, as eyewitnesses they perform the same tasks as citizens. During the investigation, both police and citizen eyewitness describe the event and perpetrator for police records. Once the case goes to trial, witnesses must testify in court about what they saw. Whether police officers are under more or less stress than citizens when experiencing criminal events, remains unclear. Police officers may experience less stress because they receive training and experience for dealing with crime events which allows them to remain calm and to apply constructive decision strategies to dangerous situations. On the other hand, police may experience more stress than the average person witnessing a crime. While citizens need only to protect themselves and avoid crime events, police must actively confront the situation, protect bystanders and themselves, and make spur-of-the-moment decisions about the level of force necessary to defuse the situation. It is these factors that may lead to increased levels of stress.
Although it is commonly thought that the ability of police officers to recall witnessed criminal activity is greater than the ability of civilians (Yarmey, 1986), very little research has been conducted comparing the amount of details correctly recalled by police and citizens. Results of these studies generally indicate that police are sometimes more accurate in their descriptive detail of criminal perpetrators and crime scene activity. These results, however, have been inconsistent (Zimmerman, 2003). If police do recall events better than citizens, and stress is related to a decrease in recall, this would seem to indicate that police experience less stress in crime situations. Very little empirical research has been conducted which directly manipulates levels of police stress in order to determine the effects on police recall accuracy. One such study by Yuille, Davies, Gibling, Marxsen and Porter (1994) found that police trainees in a stressful condition recalled fewer correct details than police trainees in a non-stressful condition. However, this study did not compare police performance to citizen performance. Because the comparison between police and citizens has rarely been made, it has remained unclear if there are differences in police and citizen accuracy under different levels of stress.
As such, two studies conducted by Stanny and Johnson (2000) sought to clarify whether: (a) officers in stressful situations experience a decrease in later recall, and (b) differences in recall ability exist between police and civilians and if those differences are related to stress levels. To assess these questions, the authors used simulated scenarios involving violent crimes which sometimes escalated into shooting incidences. Participants performed in the role of either active participants or as bystanders witnessing the crime. Prior studies have shown that active participants (i.e., victims and police) give more accurate descriptions than bystanders (Christianson & Hubinette, 1993; Hosch & Bothwell, 1990). One concern raised in these studies however was that active participants and bystanders witness the event from different points of view, with active witnesses having more access to information. After participants in the current study witnessed the event, they attempted to recall details of the scenario by completing a questionnaire concerning the incident. …