Eyewitness Testimony in a Real World Environment: Effects of Exposure Duration, Gender and Age

Transcription

1 Eyewitness Testimony in a Real World Environment: Effects of Exposure Duration, Gender and Age Abstract Eyewitness testimony is a critical form of evidence and plays a vital role in the criminal justice system. Factors that affect eyewitness testimony are explored by many psychologists. This research investigates the effects of exposure length to an event (long and short duration), the gender of the witness (male and female) and their age (under 25 and 25 & over) on recall. In this independent-measures, between-groups, experimental-design study, 20 participants are subject to an encounter with a confederate and are then approached by a researcher who asks an 8-item questionnaire about the confederate's appearance. The results suggest no significant differences for eyewitness recall based on any of the assessed factors. These results are not supported by previous studies and this would suggest that further research is warranted in exploring the effects of the tested factors on eyewitness recall. Introduction Eyewitness testimony is a formal statement offering a recollection of a specific event given by a person who has seen it occur first-hand. It is one of the most critical forms of evidence in criminal investigations (Fisher & Schreiber, 2007). Eyewitness testimony can play a very crucial role in the criminal justice system, from initial identification of a suspect to the determination of culpability in the courtroom (Benton, Ross, Bradshaw, Thomas & Bradshaw, 2006). Eyewitness evidence is frequently the source for wrongful convictions and this has sparked an interest by psychologists in factors that affect eyewitness reliability (Cutler, 1995). The three variables being explored in this study, in relation to eyewitness recall, are the participant s duration of exposure (i.e. long exposure or short exposure) to the confederate, the gender of the participant (i.e. male or female) and their age (i.e. under 25 or 25 and over). These variables build the research questions that will be

2 explored in this study. Do individuals recall more details of an event if they are exposed to it for a longer period of time? The findings of Palmer, Brewer, Weber and Nagesh (2013) suggest that they do. Their results lead them to the conclusion that there was a strong correlation between duration of exposure and accuracy. The participants exposed to a subject for a longer period of time were better able to identify them. Do males and females differ in the amount of information they recall about an event they witness? The results of a study carried out by Yarmey and Yarmey (1993) suggested there was a significant difference in the amount and accuracy of eyewitness recall. Despite being equally confident in their recall performance, it appeared that women were significantly superior to men in their recall ability and accuracy. Do younger and older adults differ in the accuracy of their recall of an event? Much previous research on the effect of age on eyewitness recall accuracy focus on the difference between children and adults. A recent study by Jack, Leov and Zajac (2014) investigated the age related differences in accounts of child, adolescent and adult witnesses. Their results suggest there were no significant differences in the accuracy of recall by the witnesses of varied ages. In contrast, another study focused solely on adults on different age groups and the results suggested that the young adults were superior to the middle-aged adults who, in turn, were superior to the older adults (Yarmey & Yarmey, 1993). These three variables have each been discussed in previous published studies. However, in this report all three variables are examined together. This allows the results to suggest if there is any correlation between each of them. This study, having been carried out in a very small and precise location, also allows the results to be applied to a very specific sub-section of the population; i.e. IADT students. The present study will test some factors thought to affect the accuracy of eyewitness recall in a real world environment. H 1 states that there will be a difference for the participants on their recall scores based on their duration of exposure to the confederate. H 2 states that there will be a difference for the participants on their recall scores based on their gender. H 3 states that there will be a difference for the participants on their recall scores based on their age.

3 Method Design This study employed an independent-measures, between-groups, experimental design. Inferential statistics used were independent t-tests to determine if significant recall differences existed between the two groups of participants, based on their duration of exposure to an event, their age and gender. Participants A total of 20 participants took part in this study. They were selected on the IADT campus and were students from a variety of courses and years. There were 10 males and 10 females selected; 5 of each group were subject to long exposure conditions and 5 to short exposure conditions. Out of the overall 20 participants, there were 10 aged under 25, and 10 were 25 and over. The mean age of participants was Materials A questionnaire (detailed in Appendix A) was used to test recall scores of each participant. This consisted of 8 questions about the confederate s appearance. A bogus questionnaire (detailed in Appendix B) was prepared to create a long duration exposure for one group of 10 participants. Consent forms (detailed in Appendix C) were required to have record of the participant s agreement to take part in the study. A debrief document (detailed in Appendix D) was also provided for each participant who took part. This gave them information about the study and provided contact details for the researchers and supervisors if they had further questions. Procedure For the short duration exposure, 10 participants were approached separately by the confederate who asked for the time. The confederate waited for a response and then continued until they were out of sight. The researcher then approached the participant and asked them if they were willing to take part in the study. If so, the researcher proceeded to ask the 8 questions about the confederate, noting the answers. Participants were provided with the relevant documentation including a debrief and

4 consent form. A signed consent form was kept by the researcher, stating the participant s agreement to take part. For the long duration exposure, another 10 participants were approached separately by the confederate who asked them to answer a short questionnaire, the bogus questionnaire. Then similarly to the procedure used for the short duration exposure, the confederate moved out of sight, the researcher approached the participant and asked if they were willing to take part. They were asked the questions and their recall scores were noted. The researcher provided the participant with a debrief and they were asked to sign a consent form. The recall score for each participant was calculated simply by adding up a total for correct answers given during the 8-item questionnaire.

5 Results The independent variables for this experiment on eyewitness testimony were: (i) (ii) (iii) Duration of Exposure Gender Age The dependent variable for this experiment was: (i) Recall Scores Analysis 1: Duration of Exposure to the Confederate (Long versus Short Duration) Descriptive Statistics: The data collected for analysis 1 is summarised in Table 1 below. The n values, mean, and standard deviation for each group (i.e., the Long and Short Duration of Exposure conditions) are presented. Table 1: Summary of recall scores collected for the participants of the two groups; Long Duration and Short Duration of Exposure. Duration of Exposure to Confederate N Mean Standard Deviation Long Duration (1) Short Duration (2) Inferential Statistics: Hypothesis 1 stated there would be a difference for the participants on their recall scores based on their duration of exposure to the confederate. In order to test this

6 hypothesis, an independent t-test was completed (2 tail; alpha = 0.05). Hypothesis 1 was not supported (t = 0.662, df = 18, p = 0.517). Analysis 2: Gender of Participant Descriptive Statistics: The data collected for analysis 2 is summarised in Table 1 below. The n values, mean, and standard deviation for each group (i.e., Female and Male) are presented. Table 2: Summary of recall scores collected for participants of the two groups; Females and Males. Gender of Participant N Mean Standard Deviation Female Male The recall scores of the participants are illustrated in Figure 1 below. This presents the recall scores of the 10 males and the 10 females questioned during analysis 2, when the factor being explored was effect of gender. Recall Scores Recall Scores Based on Gender Male Female Figure 1: Line graph representing recall score for participants of the two groups; Females and Males.

7 Inferential Statistics: Hypothesis 2 stated there would be a difference for the participants on their recall scores based on their gender. In order to test this hypothesis, an independent t-test was completed (2 tail; alpha = 0.05). Hypothesis 2 was not supported (t = 0.218, df = 18, p = 0.830). Analysis 3: Age of Participant (Over 25 versus Under 25) Descriptive Statistics: The data collected for analysis 3 is summarised in Table 1 below. The n values, mean, and standard deviation for each group (i.e., Under 25's and 25 & Over's) are presented. Table 3: Summary of recall scores collected for participants of the two groups; Under 25 and 25 & Over. Age of Participant N Mean Standard Deviation Under & Over Inferential Statistics: Hypothesis 3 stated there would be a difference for the participants on their recall scores based on their age. In order to test this hypothesis, an independent t-test was completed (2 tail; alpha = 0.05). Hypothesis 3 was not supported (t = 1.635, df = 18, p = 0.119).

8 Discussion The object of this study was to research affects certain factors had on the accuracy of recall by an eyewitness in a real world environment. The factors explored were the eyewitness s duration of exposure to the confederate, the gender of the eyewitness and their age. The findings suggest that there were no significant differences between recall ability based on any of the factors stated previously. H 1, that there will be a difference for the participants on their recall scores based on their duration of exposure to the confederate, was not supported. H 2, that there will be a difference for the participants on their recall scores based on their gender, was not supported. H 3, that there will be a difference for the participants on their recall scores based on their age, was not supported. The data that were achieved in the results do not fit the original hypotheses stated in the introduction. These results do not support previous research and would indicate that future research is warranted in the area. The result suggested by H 1 conflict with those of Palmer, et al. (2013) which had found those exposed to the subject for the longer length of time had significantly better identification ability. The result suggested by H 2 did not support previous research. Previous research that focused on the affect of gender on eyewitness recall found there was a significant difference between the recall ability of males and females. Women were significantly more accurate than men in their recall accuracy (Yarmey & Yarmey, 1993). This research was further supported by the results of a study by Areh (2011) which suggest that females significantly outperformed males in the accuracy of the descriptions of people involved in an event which they witnessed. The result suggested by H 3 did not support previous research. Yarmey and Yarmey (1993) found there to be differences in recall ability between adults of varying age groups (i.e , and 45-65). There are number of factors that influenced and altered the results of this study. Firstly, the sample tested was very small in size. A small sample size is not always a obstacle, however it does limit the ability to generalise the results to a large population. Secondly, during the procedure of this study, the participants were approached by the researcher and questioned within minutes of their encounter with the confederate. The results of Palmer, et al. (2013) suggest a correlation between

9 retention interval and accuracy. They found that there was a higher number of correct responses during the immediate testing. If there had been a longer delay between the encounter and questioning, the results may have been more true. This study, unlike many previous studies relating to eyewitness recall, addressed three separate variables rather than focusing solely on one. The technique of examining multiple variables allowed this study differ from others previously carried out. In the case of future research being carried out, caution should be exercised when deciding sample details as a larger size and more varied sample would provide a result which would be inferential to a larger population. Though the structure of the 8-item questionnaire was required and beneficial for the scoring system of the participant's recall, free-recall conditions would allow for an independent recall and would reduce the problem of chance (i.e. participants guessing correct answers). This study concludes that there are no significant differences between witnesses exposed to an event for a long duration of time and those exposed for a short duration of time, male and female witnesses or younger and older adult witnesses. However, previously research would suggest that this would not hold true if repeated with recommendations in mind.

10 References Areh, I. (2011). Gender-related differences in eyewitness testimony. Personality and Individual Differences, 50(5), Benton, T. R., Ross, D. F., Bradshaw, E., Thomas, W. N. & Bradshaw, G. S. (2006). Eyewitness memory is still not common sense: Comparing jurors, judges and law enforcement to eyewitness experts. Applied Cognitive Psychology, 20(1), Cutler, B. L. (1995). Mistaken identification: The eyewitness, psychology and the law. Cambridge University Press. Fisher, R. P., & Schreiber, N. (2007). Interviewing protocols to improve eyewitness memory. The handbook of eyewitness psychology, 1, Graham, M. H. (2003). Federal rules of evidence. St. Paul, MN: West Publishing Co. Jack, F., Leov, J., & Zajac, R. (2014). Age related differences in the free recall accounts of child, adolescent, and adult witnesses. Applied Cognitive Psychology, 28(1), Palmer, M. A., Brewer, N., Weber, N., & Nagesh, A. (2013). The confidence-accuracy relationship for eyewitness identification decisions: Effects of exposure duration, retention interval, and divided attention. Journal of experimental psychology: applied, 19(1), 55. Yarmey, A. D. (1993). Adult age and gender differences in eyewitness recall in field settings. Journal of Applied Social Psychology, 23(23),

11 Appendix A Questions to ask participants after short or long duration exposure: Male Female Points 1 Was the person female/male? Yes No Points 2 Was her/his hair longer than shoulder length? 3 Was she/he taller than me? (the researcher) 4 Was she/he wearing a hat? 5 Was she/he wearing glasses? 6 Was she/he carrying an umbrella? 7 Was her hair tied up/did he have a facial hair? 8 Did she/he have any rings on her fingers? Total

12 Appendix B Bogus questions to ask participants to provide a long duration exposure: 1. How often do visit the library in IADT? 2. What is the primary reason for you visiting the library? e.g. to study or to find resources such as books 3. Have you taken out any books in the past week?

13 Appendix C Consent Form Title of Project: A Field Study on Eyewitness Reporting Please tick box 1 I confirm that I have read and understand the information sheet for the above study and have had the opportunity to ask questions. 2 I understand that my participation is voluntary and that I am free to withdraw at any time. 3 I agree to take part in this study. 4 I understand that the data collected during this study will be kept anonymous at all times. 5 I agree to allow the data collected to be used for future research projects. (Tick to agree to participate in this study) Date Researcher 1 - Fiona Brady Date Signature Researcher 2 - Hannah O'Sheehan Date Signature

14 Appendix D Debrief Thank you very much for taking part in this research study The study in which you just participated was designed to investigate some of the factors thought to affect the accuracy of eyewitness testimonies in real world environments. If you have questions about this study, or you wish to have your data removed from the study, please contact either of us at the following addresses: N @student.iadt.ie or N @student.iadt.ie. Alternatively, you may contact my lecturers and research supervisors for this study, Dr. Olivia Hurley (olivia.hurley@iadt.ie) and Nolan O'Brien (nolan.obrien@iadt.ie) from the Department of Technology and Psychology here in IADT. We thank you sincerely for contributing to this study and assure you that your data will be kept confidential and anonymous. If published, the data will not be in any way identifiable as yours. If you have been affected by the content of this study in any way, the organisations below may be of assistance: Fiona Brady Hannah O'Sheehan

15 Appendix E Participant Score Sheet: Participant No. Duration Gender Over/Under 25 years Course Year Score 1 Short Male Under Multimedia Short Male Over Multimedia Short Female Under EMCS Short Male Over Model Making Short Female Over Applied Psych Short Female Under Animation Short Female Under Business Short Male Under Film & TV Produc Short Female Over EMCS Short Male Under Music Production Long Female Under Film & TV Produc Long Female Over Art Long Male Over EMCS Long Female Over Business Long Male Under Business Long Male Over Vis Com Long Female Under Vis Com Long Male Over Photography Long Female Under Vis Com Long Male Over Animation 3 8