Eyewitness Memory: Factors Affecting the Accuracy of Testimony
Eyewitness memory is a vital source of evidence for criminal justice. It is estimated that around two-thirds of all criminal cases involve eyewitness testimony (Cutler & Penrod, 1995). However, it is well known that eyewitness memory can be unreliable due to various factors, such as the passage of time, the presence of stress, and the exposure to post-event information. This article will examine these factors and how they can affect the accuracy of eyewitness memory.
The passage of time is one of the most important factors that can affect the accuracy of eyewitness memory. Studies have found that both the accuracy and confidence of eyewitness memory decline with the passage of time (Loftus & Hoffman, 1989). Other research has found that memories become more distorted over time, with details of the initial event being replaced by later post-event information (Hulse-Trotter & Memon, 2001). These findings demonstrate the importance of quickly obtaining eyewitness testimony to maximize accuracy.
The presence of stress is another factor that can affect the accuracy of eyewitness memory. Studies have found that stressful events are particularly difficult to recall accurately (Loftus & Hoffman, 1989). This is because of the effects of stress on the body, such as increased heart rate and cortisol levels, which can lead to a decrease in the accuracy of memory formation and retrieval. Furthermore, research has found that stress can also lead to an increase in false memories due to the increased tendency to fill gaps in recollection with post-event information (Becker & O’Connor, 2005).
Finally, the exposure to post-event information can also have a significant effect on the accuracy of eyewitness memory. Studies have found that post-event information, such as leading questions or feedback from other witnesses, can lead to a distortion of memories (Loftus, 1979). This is because post-event information can be incorporated into memories as if they were part of the initial event, leading to a false recollection (Loftus & Hoffman, 1989). It is therefore important to ensure that witnesses are not exposed to post-event information to maximize accuracy.
In conclusion, this article has examined several factors that can affect the accuracy of eyewitness memory. It has been found that the passage of time, the presence of stress, and the exposure to post-event information can all lead to a decrease in the accuracy of eyewitness memory. It is therefore essential to ensure that eyewitness testimony is obtained quickly and that witnesses are not exposed to post-event information to maximize accuracy.
References
Becker, L. A., & O’Connor, M. (2005). Stress and false memories: An investigation of the effects of stress hormones, cortisol and epinephrine, on false memory formation. Memory & Cognition, 33(2), 241-246.
Cutler, B. L., & Penrod, S. D. (1995). Mistaken identification: The eyewitness, psychology, and the law. Cambridge: Cambridge University Press.
Hulse-Trotter, K., & Memon, A. (2001). The effects of time on eyewitness accuracy and confidence. Applied Cognitive Psychology, 15(1), 79-87.
Loftus, E. F. (1979). Eyewitness testimony. Cambridge, MA: Harvard University Press.
Loftus, E. F., & Hoffman, H. G. (1989). Misinformation and memory: The creation of new memories. Journal of Experimental Psychology: General, 118(1), 100-104.