Criminal cases often hinge on the testimony of eyewitnesses; sometimes those eyewitnesses are police officers. Police eyewitnesses perform the same tasks as civilian eyewitnesses: They provide descriptions to police officers during interviews, attempt to identify perpetrators from lineups, and provide testimony during court trials. Laboratory research, along with evidence from actual court cases, has shown that eyewitness identifications are often unreliable or inaccurate. It is not clear if we can expect the abilities of a police officer as an eyewitness to be better than those of the average citizen. Findings and theories from a variety of psychological disciplines provide several hypotheses about police eyewitness performance, and research that compares police with civilian performance has produced varying results. Surveys indicate that most people believe that police eyewitness reports are more accurate and of better quality than civilian reports. When police eyewitnesses testify in court, the jury may view them as more credible, regardless of whether their identifications are indeed accurate. Psychologists sometimes testify as experts on eyewitness accuracy and face the question whether the police may be a more accurate population of eyewitnesses.
Findings from psychological research on perception and memory do not provide much evidence to support the notion that any one group of adults would perform better at eyewitness tasks. There is little evidence that certain groups of adults are inherently better at recalling and communicating the details of events or recognizing people, although there are some performance differences based on age and some variability in skill among individuals. Although some studies show that training can enhance identification abilities, others do not. Research in the area of expert cognitive processing demonstrates that as people develop domain expertise, they improve their ability to notice important details and filter out useless information. These research findings indicate, perhaps not surprisingly, that police officers may not have innately better memories but, rather, their specialized training and experience may increase their ability to recognize and recall specific details of crime situations.
Theories grounded in social psychology indicate that police eyewitnesses may be less accurate than civilians because of increased internal and external pressures to perform well. This social pressure may be particularly salient for new officers looking to impress their peers and superiors. Officers may unintentionally choose an innocent suspect from a lineup because they trust that their peers have arrested the correct suspect or they are highly motivated to capture the perpetrator. Furthermore, investigators may not use standard eyewitness safeguards with their peers, such as careful interviewing techniques and lineup instructions.
The psychological research that has directly investigated police officers as eyewitnesses provides only inconclusive answers. These studies used a wide variety of methodologies, such as live incidents, video incidents, verbal descriptions, and written descriptions, and compared police officers with a variety of civilian samples, such as college students, teachers, lawyers, and the general public. In these studies, the participants performed tasks such as providing descriptions and/or making identifications after witnessing a mock crime, distinguishing criminal activity from noncriminal activity, matching previously viewed faces with new faces, and performing eyewitness tasks while under stress.
Research comparing the police with civilians as they recall the details of an event sometimes has found that police descriptions are more detailed and accurate. When researchers examined the types of descriptive information the police and civilians provide, they found that the police provide more detail about perpetrators and the crime events. In some studies, the police show a greater tendency to perceive, or misperceive, suspicious or criminal events. Other research found no difference in description accuracy between police officers and civilians. Researchers found no differences in recall ability between police officers and civilians in stressful situations; however, both groups perform better in nonstressful than in stressful conditions. Research investigating eyewitness abilities based on police experience shows that experienced police officers outperform less experienced officers and civilians. In addition, experienced officers tend to provide more crime-specific information, such as details concerning violence and technical information related to the scene, than do newer officers and civilians.
Research tends to show that police officers and civilians are equally accurate when identifying criminal perpetrators from lineups. However, some studies found that police officers tend to misidentify innocent lineup members at greater rates than do civilians. This finding varies with experience, with newer officers making a greater number of incorrect identifications than do experienced officers.
Police officers testify as eyewitnesses in court just as do civilians. Surveys have found that jurors give greater weight to the testimony of witnesses who appear more confident. Some studies indicate that the police tend to have high confidence in their identification accuracy, irrespective of whether they are in fact correct or incorrect. Because police officers regularly testify in court and may appear more reliable as witnesses, this leaves open the possibility that jurors may weigh the accuracy and importance of police officer identifications above other evidence. When psychologists testify about eyewitness accuracy, they have only these varied results to guide them in the courtroom.
- Kassin, S. M., Tubb, V. A., Hosch, H. M., & Memon, A. (2001). On the “general acceptance” of eyewitness testimony research: A new survey of the experts. American Psychologist, 56, 405—H6.
- Yarmey, D.A. (1986). Perceived expertness and credibility of police officers as eyewitnesses. Canadian Police College Journal, 10, 31-59.
- Expert Psychological Testimony on Eyewitness Identification
- Accuracy of Eyewitness Descriptions
- Eyewitness Identification: Field Studies
- Eyewitness Memory
- Lay Beliefs about Eyewitness Memory
- Juries and Eyewitnesses
- Police Decision Making
- Training of Eyewitnesses