The Reliability of Eyewitness Testimony: A Literature Review
Summary
Eyewitness Testimony is a widespread practice in legal and judicial cases where people give an account of an event they have witnessed. The fields of forensic and cognitive psychology are concerned with this practice because although it is believed to be a generally reliable source of evidence, it still can be affected by several distortions and lead to wrongful convictions. Therefore, it is important to identify the level of eyewitness testimony’s accuracy as it may prevent or, on the contrary, create injustices in the judicial system. A wide range of research is conducted to shed light on the reliability issue of eyewitness testimony.
Studies that Support the Unreliability of Eyewitness Testimony
Most of the studies on eyewitness testimony question its credibility and highlight the factors that make human memory highly unreliable. For example, the work by Chew (2018) aims to destroy the myth that eyewitness testimony is a reliable source of forensic evidence. Referencing many previous studies in this field, he states that eyewitness memory is more fallible than people assume. He provides an example of the research conducted by the Innocence Project using DNA testing, which concluded that more than 70 percent of people were wrongfully convicted because of eyewitness misidentification (Chew, 2018). In addition, the author is concerned with why the myth about the reliability of eyewitness testimony persists. He identified several reasons, such as media and literary depictions of the witnesses’ highly detailed memories; stressfulness of the event, which implies that it should be well remembered; witnesses’ sincerity and willingness to help; and finally, confirmation bias. However, the author argues that the memory does not work as a video recorder and is prone to a number of distortions.
Furthermore, according to the research by Nandan (2022), eyewitness testimony is a fallible and unreliable source of forensic evidence as the memory is malleable. The research findings suggest that witnesses’ memory is prone to change over time under different influences such as stress, anxiety, a phenomenon of ‘weapon focus,’ leading questions, conversation with co-witnesses, the witnesses’ expectations for what should have happened, and reconstructive memory.
The author believes jurors and the legal system should not trust and rely so much on eyewitness testimony.
The study used 100 graduate and postgraduate students from different professions between 20 and 30 years. A hypothesis under investigation was: “The eyewitness reliability decreases as the period increases between the incident and courtroom trial” (Nandan, 2022, p. 5450). The participants were asked to watch a video and describe it in a written format. After two weeks, they were asked to recall the video and describe it again without seeing the video. According to the study results, more than half of the respondents’ answers did not match their initial replies to the same questions due to some influencing factors like reconstructive memory, leading questions, stress, and anxiety (Nandan, 2022). The witnesses might be unaware of their errors and be confident about the given answers. Therefore, the author concludes that despite its widespread use in the judicial system, eyewitness testimony cannot be a reliable source of information and lead to the conviction of innocent people.
Factors that Affect the Eyewitness Memory
Some of the research on eyewitness testimony is also concerned with what factors can distort the accuracy of eyewitness identification. In the study by Liu (2021), the author analyzes two important factors, how witnesses are questioned and their mental state, that can influence eyewitness memory and its reliability. According to the research findings, certain questions asked during eyewitness testimony and suggestive information can make witnesses provide misleading information. In addition, the stress conditions, as well as different emotional tones, can also negatively impact the accuracy of the evidence. The author states that a growing number of studies reveal the unreliable nature of eyewitness testimony due to its vulnerability to different environmental and personal factors.
The first aspect that was of particular interest to the author is the issue of questioning style. According to the researcher, inappropriate questioning styles, including suggestive questions, high tone of voice, and expressions, can adversely impact the accuracy of the obtained information (Liu, 2021). The author references the previous research conducted by other scholars and explains the phenomenon of ‘false memory’ derived from false cues used in the suggestive questions. In other words, the misinformation used in the suggestive questions can affect the accuracy of the eyewitness memory. In addition, the type of asked questions can also influence the reliability of the testimony. The author provides an example of the research that concluded that answers to open-ended questions were more accurate than the questions with yes or no answers (Liu, 2021). Thus, to avoid biased and inaccurate information during the eyewitness testimony, it is better to ask primarily open-ended questions.
Another factor that greatly influences the testimony’s reliability is the witness’s mental state and emotions. The author argues that different emotions affect the encoding and storing of memory. For example, memory capacity tends to be stronger when people experience negative emotions rather than positive or neutral ones. Moreover, according to the researcher, emotions can lead to the extraction of false memory, distorting the actual event’s memory. Secondly, the details that seem important to the witnesses can impair the information of the whole event. The author gives an example of the “weapon focus effect,” which demonstrates that when the weapon appears during the event, almost all of the witness’s attention switches to it, and they can miss other important features (Liu, 2021). These factors show that human memory is plastic and can sometimes cause misinformation and inaccurate testimony.
Another study by Nayak & Khajuria (2019) reveals the issues related to the reliability of eyewitness testimony and what kind of psychological and social factors influence the accuracy of the provided information by an eyewitness. According to the research findings, the internal factors that can affect the truthfulness of the eyewitness testimony are related to the psychology or biology of the witnessing, which involves age, attention, stress level, personal biases, prejudices, prior experience, degree of certainty, skill, motivation, gender and cognitive state (Nayak & Khajuria, 2019). The factors such as contextual information and degree of certainty are found to have an important influence on the decision-making process. Among external or environmental factors is the time of duration of exposure, distance, lightning conditions, loud noise, event timing, and others.
The paper by Oran (2019) is concerned with the aspects that can both positively and negatively influence the level of accuracy of eyewitness testimony. The author draws her conclusion based on the study findings. According to the study findings, the more time passes after the event, the more likely the eyewitness testimony will be inaccurate (Oran, 2019). Therefore, the author believes that in real-life situations, there is a higher chance for eyewitness testimony to be reliable if court proceedings are conducted soon after the original event.
The researcher created an online presentation tool describing the original crime scene for this study. Five participants were asked to read and look at this presentation for only five minutes. Afterward, for three weeks, these subjects were asked to answer seven same questions four times in the form of a survey. The first two sets of questions were answered the day of the presentation and the day after it. The further set of questions was answered a week after the last set of questions. The results showed that the respondents provided the most accurate and detailed information on the day of the presentation and the day after it. Subsequently, the answers to the questions started to become vague, detailed and even misleading. The research demonstrated that the period between the actual crime and the survey about the crime scene could directly influence the reliability of the eyewitness testimony (Oran, 2019). Therefore, the author suggests that eyewitness testimony in the courtroom should be conducted as soon as possible after the original crime as the level of remembrance of vital details of the crime worsens with time.
Studies that Support the Reliability of Eyewitness Testimony
Although the prevailing number of researches done on eyewitness testimony has the same verdict that it is unreliable and does not believe in its validity, some studies still contradict the widespread belief. For example, the main statement of the study conducted by Wixted et al. (2018) is that eyewitness testimony or memory can serve as a reliable source of evidence in the legal system if it is not contaminated and applied under all proper testing procedures. In addition, the researchers state that most of the mistakes eyewitnesses make are made by other actors involved in the process. This research contradicts the previous belief held by a prevailing number of psychologists that eyewitness memory is unreliable because human memory is malleable.
The authors believe that when the eyewitness evidence gathered via either recognition or recall tests is reliable in case specific conditions are met. They include when witnesses are not exposed to the contaminating information before; witnesses’ memory is studied for the first time; witnesses are not inclined to give the desired evidence via biased lineups or suggestive questions; witnesses’ metacognitive monitoring corresponds to their responses; and investigators take into account the level of witnesses’ confidence (Wixted et al., 2018). Moreover, according to the research findings, eyewitness testimony is as reliable as DNA evidence. Therefore, the authors conclude that when all the proper testing procedures are followed and information is not contaminated, eyewitness memory is proven reliable and can be used in federal trials with the same confidence level as DNA test results.
The conclusion provided by the researchers of this article contradicts the prevailing number of other scientific works on the reliability of eyewitness memory. Based on the research findings, most of the psychology community believes that eyewitness testimony cannot be a strong source of evidence and can lead to the imprisonment of innocent people. The motivation behind such a conclusion is to prevent people from believing eyewitness testimony is mostly reliable. According to the American Psychological Association’s findings, even eyewitnesses with a high confidence level (from 90 to 100 percent) were mistaken in 40 percent of cases (Wixted et al., 2018). But still, eyewitness testimony keeps being used in the judiciary system. All of these claims were evoked by experimental psychologists who concluded that the human memory, which is actively involved in the process of eyewitness testimony, was malleable and could be easily contaminated.
Nevertheless, Wixted et al. (2018) do not agree with this verdict. Providing an analogy with DNA testing, the authors state that all forensic evidence, including the DNA test results, can be contaminated if improper testing procedures are not applied. The cases of DNA test contaminations can be rare as the approved requirements in the laboratory protocols are usually followed. Therefore, the possibility of contamination does not directly mean unreliability of the results of the evidence (Wixted et al., 2018). Secondly, in the DNA testing system, there is also a possibility of a wrongful conviction if the random-match probability is not considered. If the indicator of random-match likelihood is low, the evidence is not proven to be strong and cannot be used as a strong source of information. This is the criminal system’s fault, not the DNA test results that ignore the random-match probability. The DNA test results, however, are not believed to be inherently unreliable as the eyewitness testimony.
The authors of this research draw their conclusion based on the study concerned with the connection between the level of witnesses’ confidence and the accuracy of the provided evidence in recognition tests (using lineups) and recall (during police interviews). They concluded that during the recognition tests if all proper testing procedures are used, and the witness’s memory is not contaminated, the high level of eyewitness confidence implies the high accuracy of the provided evidence. The witness’s memory is found to be uncontaminated when tested for the first time. Any further testing of the provided information leads to memory contamination. In addition, through the laboratory studies to check the reliability of eyewitness memory in the recall tests, the researchers found that the cognitive interviews were much more accurate than alternative interviews and supported the notion that the eyewitness testimony was reliable. Therefore, the authors believe eyewitness testimony is a reliable source of information if specific conditions are followed and can be used in the criminal justice system.
Enhancing the Reliability of Eyewitness Testimony
Some studies accept that eyewitness testimony is not the most reliable source of forensic evidence and that it is still used in the legal system. Therefore, they propose several solutions to enhance the level of eyewitness identification. The research conducted by Sumampouw et al. (2021) is concerned with the level of knowledge that the legal and non-legal professionals in the judicial system possess about eyewitness testimony and how it affects the accuracy of the obtained evidence. The authors state that eyewitness testimony is a practice that is widely used in the criminal justice system and is heavily relied on when there is a lack of other forensic evidence. However, the numbers demonstrate that eyewitness testimony can lead to mistaken convictions and sentencing innocent people. Therefore, the researchers aimed to identify the knowledge of police officers compared to psychologists about eyewitness testimony and whether or not the knowledge level impacts eyewitness memory’s reliability. The research findings conclude that in Indonesia, most police officers who practice eyewitness testimony in their work have less knowledge about it than psychologists. Furthermore, due to the lack of this knowledge, people in the legal system tend to make errors in assessing and conducting eyewitness identification. This misusage of eyewitness testimony leads to wrongful convictions and belief in its unreliability.
The current study involved a sample of 270 police officers and 63 clinical psychologists who examined the viability of the eyewitness testimony given by adults and children. The participants were asked to answer questions in the questionnaire about eyewitness testimony. According to the respondent’s answers, the majority of both groups have never been exposed to the materials on the eyewitness testimony and, therefore, have no experience or knowledge of this type of forensic evidence. However, most respondents have been involved in the eyewitness testimony procedure involving children as witnesses. In the group of psychologists, only a small number of people served as trial experts.
Based on the results, it was concluded that clinical psychologists possessed more information regarding eyewitness testimony than police officers, although the overall results showed that both groups lacked knowledge about important factors that affected the accuracy of the eyewitness testimony. The fact that legal and non-legal professionals involved in the criminal justice system have limited knowledge about important aspects of eyewitness memory can undermine the accuracy of the obtained evidence and negatively affect the reliability of the eyewitness testimony. Thus, the authors conclude that there is a need to conduct training and enhance the education level of Indonesian professionals to avoid cases of wrongful convictions in the legal system.
Furthermore, the work by Puddiffot (2018) proposes to educate jurors using psychological findings to avoid false convictions during eyewitness testimony. Unlike most of the arguments that state that jurors tend to possess an unacceptable level of credibility towards eyewitness testimony, judging it to be reliable when it is not, the work by Puddiffot (2018) claims that jurors can undermine the credence of some pieces of eyewitness testimony. The author believes that jurors should be acknowledged by the psychological findings to avoid cases where they lower the credence of eyewitness testimony, being susceptible to the misinformation effect. Moreover, the author also supports the claim that eyewitness testimony is more reliable than it is widely perceived to be. According to the study, “it is appropriate to lower the credence given to an individual piece of eyewitness testimony only if, in so doing, one increases the chance of a correct verdict being reached about the case in which the testimony is used” (Puddifoot, 2018, p. 260). Otherwise, the jurors should objectively assess the credibility of the evidence without lowering the credence of the eyewitness testimony. By reducing the credence given to the evidence from the eyewitness testimony, jurors may also lower the chance of a correct verdict.
To support her argument, the researcher provides a number of cases where the jurors discredited the reliability of a piece of eyewitness evidence due to minor and unimportant errors in the witnesses’ testimony. In most of these cases, the jurors concluded that witnesses provided false information to deceive or that they did not possess a good supply of evidence about the event. However, the findings showed that the errors made by the witnesses were small and did not significantly affect the accuracy of the provided information. Those minor mistakes made jurors skeptical about the testimony and resulted in the non-acceptance of the witnesses’ testimony. The author concludes that the jurors should be given education about cognitive science literature that will show that witnesses can make small errors while having a good supply of memory about the event. This literature can also help jurors to identify where witnesses have an intention to deceive or have an inadequate supply of memory about the crime and where there is only a human operation of cognitive mechanisms.
References
Chew, S. L. (2018). Myth: Eyewitness testimony is the best kind of evidence. Association for Psychological Science. Web.
Liu, F. (2021). The reliability of eyewitness testimony. In Proceedings of the 2021 International Conference on Public Relations and Social Sciences (pp. 593-596). Atlantis Press.
Nandan, A. (2022). Eyewitness testimony: A psychological and legal perspective. Journal of Positive School Psychology, 6(6), 54466-5453.
Nayak, B. P., & Khajuria, H. (2019). Eyewitness testimony: Probative value in the criminal justice system. Egyptian Journal of Forensic Sciences, 9(2). Web.
Oran, M. E. (2019). Research on the reliability of eyewitness testimony based on an online study. Instars: A Journal of Student Research, 5.
Puddifoot, K. (2018). Re-evaluating the credibility of eyewitness testimony: The misinformation effect and the overcritical juror. Episteme, 17(2), 255-279. Web.
Sumampouw, N., Bjørndal, L. D., Magnussen, S., Otgaar, H., & Brennen, T. (2021). Knowledge about eyewitness testimony: A survey of Indonesian police officers and psychologists. Psychology, Crime & Law, 1-15. Web.
Wixted, J. T., Mickes, L., & Fisher, R. P. (2018). Rethinking the reliability of eyewitness memory. Perspectives on Psychological Science, 13(3), 324-335. Web.