Stopping crime? The effect of crime re-enactments on eyewitness memory

Abstract

Crime re-enactments broadcast on television encourage witnesses to provide information regarding unsolved crimes. However, given that eyewitness memory can be altered through exposure to post-event information, it is possible that crime re-enactments may influence the memory of eyewitnesses. The current studies examined the effects of crime re-enactments on eyewitness memory. In two experiments (Experiment 1 with a distractor task, Experiment 2 without a distractor task), participants were shown one of three versions of a crime video that differed in their ambiguity. One week later half of the participants viewed a crime re-enactment. All participants then completed a guided free- and cued-recall task regarding the original event. Across both studies, exposure to the re-enactment did not improve eyewitness memory; instead, participants who viewed the re-enactment were more likely to accept the misinformation in the re-enactment. The findings shed light on potential issues with using crime re-enactments to elicit eyewitness accounts.

Keywords:

• context reinstatement
• crime re-enactment
• crime stoppers
• eyewitness memory
• memory
• misinformation effect
• post-event information

Ethical standards

Declaration of conflicts of interest

Hayley Cullen has declared no conflicts of interest

Helen Paterson has declared no conflicts of interest

Celine van Golde has declared no conflicts of interest

Ethical approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the University of Sydney Human Research Ethics Committee [protocol number 2015/315] and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study

Acknowledgements

The authors would like to thank Michael Spoelma, Claire Maddox, and Hannah Ebrahimiyan for their assistance with data coding.

Notes

1 For completeness of cued recall, while it was again found that participants who saw the ambiguous crime provided significantly more detail than participants who saw the no crime video, additionally participants who saw the unambiguous crime provided significantly more correct detail (M = 16.46, SD = 6.85) than participants who saw the no crime video (M = 9.17, SD = 6.26), F(1, 128) = 18.124, p < .001, η²_p = .124.

2 There was a significant main effect of crime ambiguity, F (2, 128) = 3.889, p = .023, η²_p = .057. Post hoc contrasts revealed that participants who viewed the unambiguous crime reported significantly more correct PEI during cued recall (M = 8.96, SD = 4.34) than participants who viewed the no crime video (M = 6.30, SD = 4.61), F(1, 128) = 6.992, p = .009, η²_p = .052. There was also a significant main effect of crime re-enactment, F(1, 128) = 7.849, p = .006, η²_p = .058. Participants who viewed the re-enactment reported significantly more correct PEI items (M = 9.03, SD = 5.02) than participants not shown the re-enactment (M = 6.76, SD = 4.49).

3 For cued recall, there was a significant effect of crime ambiguity on number of misinformation items reported, F(2, 128) = 4.007, p = .021, η²_p = .059. The only post hoc contrast that was significant was that those who observed the unambiguous crime (M = 1.00, SD = 1.24) reported significantly more misinformation than those who observed no crime (M = 0.44, SD = 0.80), F(1, 128) = 7.869, p = .006, η²_p = .058.

4 For cued recall, participants within the ambiguous crime condition reported significantly more misinformation when they viewed the re-enactment (M = 1.09, SD = 0.90) than when they did not (M = 0.48, SD = 0.73), F(1, 44) = 6.341, p = .016, η²_p = .126. Likewise, participants within the unambiguous crime condition reported significantly more misinformation during cued recall when they viewed the re-enactment (M = 1.48, SD = 1.41) than when they did not (M = 0.50, SD = 0.80), F(1, 43) = 8.084, p = .007, η²_p = .158.

5 A significant main effect of crime ambiguity was found for statement accuracy in cued recall, F(2, 128) = 4.886, p = .009, η²_p = .071. Post hoc contrasts showed that the only contrast that lasted through Bonferroni corrections was that participants who saw the unambiguous crime were significantly more accurate in cued recall (M = 73.76, SD = 14.80) than participants who saw the no crime video (M = 58.84, SD = 29.76), F(1, 128) = 8.938, p = .003, η²_p = .065.

6 For completeness of cued recall, post hoc contrasts revealed that participants who saw the ambiguous crime (M = 18.93, SD = 7.77) provided significantly more correct detail than participants who saw the no crime video (M = 11.82, SD = 6.26), F(1, 156) = 29.446, p < .001, η²_p = .159, and participants who saw the unambiguous crime (M = 15.25, SD = 5.99), F(1, 156) = 8.024, p = .005, η²_p = .049. Participants who saw the unambiguous crime also provided significantly more correct detail than participants who saw the no crime video, F(1, 156) = 6.925, p = .009, η²_p = .043.

7 During cued recall, there was a significant main effect of crime ambiguity on the number of incorrect details reported, F(2, 156) = 5.965, p = .003, η²_p = .071. Post hoc contrasts revealed that participants who viewed the ambiguous crime (M = 5.82, SD = 2.98) reported significantly more incorrect details than participants who viewed the no crime video (M = 4.03, SD = 2.96), F(1, 156) = 11.139, p = .001, η²_p = .067, and those who viewed the unambiguous crime (M = 4.53, SD = 2.23), F(1, 156) = 5.948, p = .016, η²_p = .037.

8 For number of correct PEI items reported during cued recall, there was a significant main effect of crime ambiguity, F(2, 156) = 4.860, p = .009, η²_p = .059. Post hoc contrasts revealed that participants who viewed the ambiguous crime reported significantly more correct PEI (M = 9.54, SD = 3.31) than participants who saw the no crime video (M = 7.64, SD = 3.40), F(1, 156) = 9.024, p = .003, η²_p = .055. No other contrasts were significant.

9 In cued recall, there was also a significant difference in the number of misinformation items reported based on crime ambiguity, F(2, 156) = 8.097, p < .001, η²_p = .094. Post hoc contrasts revealed that participants in the ambiguous crime condition reported significantly more misinformation (M = 1.81, SD = 1.29) than participants in the no crime condition (M = 1.04, SD = 1.00), F(1, 156) = 13.655, p < .001, η²_p = .080, and than participants in the unambiguous crime condition (M = 1.15, SD = 0.95), F(1, 156) = 10.414, p = .002, η²_p = .063. However, there was no difference between the no crime condition and unambiguous crime condition in number of misinformation items reported during cued recall, F(1, 156) = 0.250, p = .618, η²_p = .002.

10 In cued recall, there was no difference within each crime condition in regard to misinformation reported.