The effects of acute stress on eyewitness memory: an integrative review for eyewitness researchers

The eyewitness and fundamental memory research fields have investigated the effects of acute stress at encoding on memory performance for decades yet results often demonstrate contrasting conclusions. In this review, we first summarise findings on the effects of acute encoding stress on memory performance and discuss how these research fields often come to these diverging findings regarding the effects of encoding stress on memory performance. Next, we critically evaluate methodological choices that underpin these discrepancies, emphasising the strengths and limitations of different stress-memory experiments. Specifically, we elaborate on choice of stressors and stimuli, stress manipulation checks, stressor timing, and the interval between encoding and retrieval and discuss how methodological shortcomings in both the eyewitness and fundamental memory fields have limited our understanding of how encoding stress may affect eyewitness memory performance. Finally, we propose several recommendations for researchers interested in this topic, such as confirming stress inductions with physiological measures, implementing sufficient retrieval intervals to isolate the memory phase of interest and using ecologically valid memory paradigms. We conclude that the best progress can be made if researchers are responsive to the methodologies and findings reported in other research fields and encourage collaborations between the different disciplines.

The impact of recall timing on the preservation of eyewitness memory

Two studies investigated the impact of recall timing on eyewitness memory. In Study 1, participants viewed a crime video and then completed the Self-Administered Interview (SAI^©) either immediately, after a 24-h delay, after a 1-week delay, or not at all. All participants completed a final recall questionnaire 2 weeks after they had viewed the stimulus video. Study 2 aimed to determine how long the beneficial impact of the SAI^© on witnesses' long-term memory lasts. Participants watched a crime video and then either completed the SAI^© or did not engage in an immediate recall attempt. Participants then completed a final recall questionnaire after a delay of 24 h, 1 week, 2 weeks, or 1 month. The results indicated that initial recall should be completed within 24 h of an incident and that under these conditions, the beneficial impact of early recall on long-term memory endures for at least 1 month.

The Dynamic and Fragile Nature of Eyewitness Memory Formation: Considering Stress and Attention

Eyewitnesses are often susceptible to recollection failures and memory distortions. These failures and distortions are influenced by several factors. The present review will discuss two such important factors, attention failures and stress. We argue that acute stress, often experienced by eyewitnesses and victims of crimes, directly influences attentional processes, which likely has downstream consequences for memory. Attentional failures may result in individuals missing something unusual or important in a complex visual field. Amongst eyewitnesses, this can lead to individuals missing details, even unusual or important central details, regarding the crime. Surprisingly, few studies have investigated attentional failures in eyewitness scenarios, and none have investigated the relationship between stress, attention, and witness memory. This review will discuss the impact of attentional failures, mainly those resulting from inattentional blindness, in applied contexts in order to bridge to eyewitness scenarios. In addition, we will integrate the applied literature on attentional failures with literature that examines the influences of arousal and stress on attention. We will conclude by presenting how future research may tease apart the independent contributions of arousal and stress on attentional failures and successes and how this research may inform understanding of eyewitness reliability.

Lessons for the courtroom from the study of Flashbulb memory: an integrative review

In legal proceedings, when no corroboration is possible with external sources of evidence, judges and jurors derive from their own experience the criteria to ascertain if a memory report is accurate and a witness credible. These legal criteria closely resemble the aspects traditionally investigated by literature on Flashbulb memory (i.e., consistency, confidence, quantity), but have failed to obtain a generalised consensus within the scientific community. Drawing up a set of univocal rules upon which to base a conclusion regarding witnesses' credibility is a difficult task, from both legal and scientific points of view. Respectful cooperation between cognitive science and criminal law will encompass both technical support by expert witnesses, and updating guidelines for fact-finders. This cooperation would prevent the risk of common sense fallacies in the legal process, preserving the legal autonomy to evaluate witness credibility.

The Impact of Testing on the Formation of Children's and Adults' False Memories

Witnesses are frequently questioned immediately following a crime. The effects of such testing on false recall are inconclusive: Testing may inoculate against subsequent misinformation or enhance false memory formation. We examined whether different types of processing can account for these discrepancies. Drawing from Fuzzy-trace and Associative-activation theories, immediate questions that trigger the processing of the global understanding of the event can heighten false memory rates. However, questions that trigger the processing of specific details can inoculate memories against subsequent misinformation. These effects were hypothesized to be more pronounced in children than in adults. Seven/eight-, 11/12-, 14/15-year-olds, and adults (N = 220) saw a mock-theft film and were tested immediately with meaning or item-specific questions. Test results on the succeeding day replicated classic misinformation and testing effects, although our processing hypothesis was not supported. Only adults who received meaning questions benefited from immediate testing and, across all ages, testing led to retrieval-enhanced suggestibility. © 2016 The Authors. Applied Cognitive Psychology Published by John Wiley & Sons, Ltd.

Stress, stress-induced cortisol responses, and eyewitness identification performance

In the eyewitness identification literature, stress and arousal at the time of encoding are considered to adversely influence identification performance. This assumption is in contrast with findings from the neurobiology field of learning and memory, showing that stress and stress hormones are critically involved in forming enduring memories. This discrepancy may be related to methodological differences between the two fields of research, such as the tendency for immediate testing or the use of very short (1-2 hours) retention intervals in eyewitness research, while neurobiology studies insert at least 24 hours. Other differences refer to the extent to which stress-responsive systems (i.e., the hypothalamic-pituitary-adrenal axis) are stimulated effectively under laboratory conditions. The aim of the current study was to conduct an experiment that accounts for the contemporary state of knowledge in both fields. In all, 123 participants witnessed a live staged theft while being exposed to a laboratory stressor that reliably elicits autonomic and glucocorticoid stress responses or while performing a control task. Salivary cortisol levels were measured to control for the effectiveness of the stress induction. One week later, participants attempted to identify the thief from target-present and target-absent line-ups. According to regression and receiver operating characteristic analyses, stress did not have robust detrimental effects on identification performance. Copyright © 2016 John Wiley & Sons, Ltd. © 2016 The Authors Behavioral Sciences & the Law Published by John Wiley & Sons Ltd.