Do distress responses to a traumatic film predict susceptibility to the misinformation effect?

A systematic review of the relationship between emotion and susceptibility to misinformation

Inaccurate memory reports can have serious consequences within forensic and clinical settings, where emotion and misinformation are two common sources of memory distortion. Many studies have investigated how these factors are related; does emotion protect memory or leave it more vulnerable to the distorting effects of misinformation? The findings remain diffused. Thus, the present review aimed to clarify the relationship between emotion and susceptibility to misinformation. 39 eligible studies were reviewed. Results varied according to the type and dimension of emotion measured. Level of arousal may be unrelated to susceptibility to misinformation when retrieval occurs without delay; studies including delayed retrieval were limited. Stimuli valence may be associated with increased susceptibility to peripheral misinformation but unrelated to other misinformation. The following results were reported by limited studies: short-term distress and moderate levels of stress may decrease susceptibility, while anger and greater cortisol response to stress may increase susceptibility to misinformation. Source memory may also be unaffected by emotion. The results have important potential implications for forensic and clinical practice, for example by highlighting the value of enquiring witnesses' source memory. Methodological recommendations for future studies are made.

False denials increase false memories for trauma-related discussions

False denials are sometimes used to cope with traumatic experiences. We examined whether false denials can affect true and false memory production for a traumatic event and conversations surrounding the trauma. One hundred and twenty-six participants watched a trauma analogue video of a car crash before being randomly asked in a discussion with the experimenter to (1) respond honestly or (2) falsely deny that certain details happened in the video. After one week, all participants received misinformation about the discussion with the experimenter and the car crash. Finally, all participants were instructed to respond truthfully in a source memory task. Participants who falsely denied information during the first session were statistically significantly more prone than honest participants to omit details they denied and to report misinformation about what was discussed in the first session. Our work suggests that false denials of a traumatic experience might lead to both forgetting and increased false memory levels for earlier conversations about the event.

The role of belief in memory amplification for trauma events

BACKGROUND AND OBJECTIVES

Trauma survivors often report trauma events inconsistently over time. Many studies, for example, have found that people report having experienced trauma events that they initially failed to report or remember, a phenomenon called "memory amplification." Other studies have found the opposite: people report experiencing fewer events over time. Nahleen, Nixon, and Takarangi (2019) asked participants at two time-points, with a six-month delay, whether they had experienced 19 sexual assault events on a yes/no scale. Participants reported fewer events over time, that is, memory for sexual assault did not amplify overall. In the current study, we assessed whether inconsistency in reports of trauma exposure over time may be attributed to changes in participants' belief that certain events were experienced.

METHODS

We replicated Nahleen et al. (2019), but rather than respond to a yes/no trauma exposure scale, participants were required to rate the likelihood that each trauma event occurred on an 8-point scale (1 = definitely did not happen; 8 = definitely did happen).

RESULTS

We found that participants believed that they were less likely to have experienced the sexual assault events at follow-up compared to initial assessment.

LIMITATIONS

We could not corroborate trauma experiences or determine causality with our design. Further, not all of our findings were consistent with Nahleen et al. (2019).

CONCLUSIONS

Sexual assault memories did not amplify over time, perhaps because, compared to other types of trauma, the idea of experiencing additional sexual assault events that were not actually experienced is less believable.

Does emotional or repeated misinformation increase memory distortion for a trauma analogue event?

In general, memory of highly negative and even traumatic events can distort. However, the effect of misinformation exposure on such memories requires further investigation given the inconsistent past findings. With two experiments, we investigated: (1) whether misinformation distorts memory for highly negative analogue events, (2) whether memory distortion is increased for more emotional and potentially traumatic details compared to unemotional details, and (3) whether repeated misinformation exposure further increases memory distortion for highly negative events compared to single exposure, a possibility that has not been investigated to our knowledge. In both experiments, participants viewed a trauma analogue film with some scenes removed. Twenty-four hours later, they were given three "eyewitness" reports describing the film's events. To manipulate misinformation repetition, either zero, one, or all three of the reports described removed scenes. To determine whether memory distortion is increased for emotional details, half of the removed scenes were more traumatic than the other half. Participants exposed to misinformation falsely remembered more removed scenes compared to participants who were not exposed to misinformation. Further, memory distortion was increased for emotional (vs. unemotional) aspects of the film. Repeated misinformation exposure, however, did not lead to significantly higher error rates compared to single exposure. The lack of perceptual overlap between our written misinformation and film test items may have limited false memories even with repeated misinformation. Alternatively, the repeated vs. single misinformation effect may exist but be very small, as suggested by our raw means and effect sizes.

A novel virtual reality paradigm: Predictors for stress-related intrusions and avoidance behavior

BACKGROUND AND OBJECTIVES

Most people are exposed to a violent or life-threatening situation during their lives, but only a minority develops a stress-related disorder. To examine risk factors for the development of stress-related symptoms, such as intrusions and avoidance, analogue trauma studies are necessary. The often-used trauma film paradigm has proven to be valuable to examine intrusions, but inherently to its technique is less suitable for assessing behavioral avoidance, a core symptom of stress-related disorders. The aim of the present study was twofold, first to further develop an analogue that explicitly addresses behavioral avoidance and second, to link previously-established risk factors for the development of stress-related symptoms.

METHOD

Eighty-two healthy participants were subjected to a trauma induction using virtual reality (VR). At follow-up, participants were placed in a similar VR environment and could approach or avoid the trauma-scene, a trauma-related scene or a neutral, unrelated scene. Several pre- and peri-trauma risk factors were measured.

RESULTS

The VR paradigm increased negative mood and heart rate, decreased positive mood and heart rate variability, and resulted in stress-related symptoms as trauma-related thoughts and beliefs, intrusions and avoidance behavior. The most prominent risk factors that contributed to the stress-related symptoms were negative emotions during the trauma induction, trait anxiety, and avoidant coping strategies.

LIMITATIONS

The stress-related symptoms were mild, resulting in a vast amount of participants without intrusions and limited avoidance behavior.

CONCLUSION

The current VR paradigm can elicit stress-related symptoms, including avoidance; risk factors contributing to these symptoms were similar to those observed in clinical research, indicating the potential of the general set up.

The effects of repeatedly recalling a traumatic event on eyewitness memory and suggestibility

The aims of this study were to examine the effects of repeatedly recalling a traumatic event on recall performance and eyewitness suggestibility. We also investigated whether these effects were moderated by the type of details recalled and the completeness of retrieval. Participants watched a video depicting a fatal car accident and were randomly allocated to one of four conditions in which they: (1) repeatedly recalled the traumatic (central) details of the event only (trauma-focused); (2) repeatedly recalled the non-traumatic (peripheral) details of the event only (non-trauma focused); (3) repeatedly recalled the entire video (complete); or (4) did not recall the video at all (no-recall control). Results indicated that repeated complete recall was beneficial for memory retention of the entire traumatic event and that, in general, trauma-related (central) post-event information (PEI) was less likely to be reported than trauma-unrelated (peripheral) PEI. It was also found that repeated trauma-focused recall increased trauma-related confabulations. These results not only illustrate the value of repeated complete recall to best preserve the integrity of eyewitness memory, but, perhaps more critically, warn of the dangers of repeatedly questioning witnesses specifically about the central or traumatic details of an event.

Imagining trauma: Memory amplification and the role of elaborative cognitions

BACKGROUND AND OBJECTIVES

Trauma victims, such as war veterans, often remember additional traumatic events over time: the "memory amplification effect". This effect is associated with the re-experiencing symptoms of post-traumatic stress disorder (PTSD), including frequent and intrusive images of the trauma. One explanation for memory amplification is that people gradually incorporate new, imagined information about the trauma with what they actually experienced, leading to an amplified memory for what actually happened. We investigated this proposal here.

METHODS

Participants viewed highly negative and graphic photographs and recorded their intrusions. Critically, we instructed some participants to elaborate on their intrusions-that is, we asked them to imagine details about the trauma beyond what they actually witnessed. We assessed memory for the traumatic photos twice, 24-h apart.

RESULTS

The elaboration condition experienced fewer intrusions about the photos compared to the control condition. Furthermore, the elaboration condition were less susceptible to memory amplification compared to controls.

LIMITATIONS

The use of negative photos allowed experimental control, however does not permit generalization of our findings to real-world traumatic experiences.

CONCLUSIONS

Our findings suggest that effortful imagination of new trauma-related details leads to a reduction in intrusions and an increased tendency to not endorse trauma exposure over time. One explanation for this finding is that elaboration enhanced conceptual processing of the trauma analogue, therefore reducing intrusions. Critically, this reduction in intrusions affected participants' tendency to endorse trauma exposure, which is consistent with the reality-monitoring explanation for memory amplification.

Do emotional stimuli enhance or impede recall relative to neutral stimuli? An investigation of two "false memory" tasks

Many eyewitness memory situations involve negative and distressing events; however, many studies investigating "false memory" phenomena use neutral stimuli only. The aim of the present study was to determine how both the Deese-Roediger-McDermott (DRM) procedure and the Misinformation Effect Paradigm tasks were related to each other using distressing and neutral stimuli. Participants completed the DRM (with negative and neutral word lists) and viewed a distressing or neutral film. Misinformation for the film was introduced and memory was assessed. Film accuracy and misinformation susceptibility were found to be greater for those who viewed the distressing film relative to the neutral film. Accuracy responses on both tasks were related, however, susceptibility to the DRM illusion and Misinformation Effect were not. The misinformation findings support the Paradoxical Negative Emotion (PNE) hypothesis that negative stimuli will lead to remembering more accurate details but also greater likelihood of memory distortion. However, the PNE hypothesis was not supported for the DRM results. The findings also suggest that the DRM and Misinformation tasks are not equivalent and may have differences in underlying mechanisms. Future research should focus on more ecologically valid methods of assessing false memory.

Memory amplification for trauma: Investigating the role of analogue PTSD symptoms in the laboratory

Victims of trauma often remember their experience as being more traumatic later, compared to immediately after, the event took place. This finding-the "memory amplification effect"-is associated with increased re-experiencing symptoms. However, the effect has been found almost exclusively in field-based studies. We examined whether the effect could be replicated in the laboratory. In two studies, we exposed participants to negative photographs and assessed their memory for the photographs and analogue PTSD symptoms on two occasions. In Study 1, analogue symptoms at follow-up were positively associated with remembering more negative photos over time. In Study 2, we focused on "memory amplifiers": people whose memory of the photos amplified over time. Consistent with field research, analogue re-experiencing symptoms were associated with memory amplification. Overall, our findings confirm that analogue PTSD symptoms are also associated with an amplified memory for a trauma analogue.

Cortisol response and psychological distress predict susceptibility to false memories for a trauma film

For eyewitness testimony to be considered reliable, it is important to ensure memory remains accurate following the event. As many testimonies involve traumatic, as opposed to neutral, events, it is important to consider the role of distress in susceptibility to false memories. The aim of this study was to investigate whether cortisol response following a stressor would be associated with susceptibility to false memories. Psychological distress responses were also investigated, specifically, dissociation, intrusions, and avoidance. Participants were allocated to one of three conditions: those who viewed a neutral film (N = 35), those who viewed a real trauma film (N = 35), and a trauma "reappraisal" group where participants were told the film was not real (N = 35). All received misinformation about the film in the form of a narrative. Participants provided saliva samples (to assess cortisol) and completed distress and memory questionnaires. Cortisol response was a significant predictor of the misinformation effect. Dissociation and avoidance were related to confabulations. In conclusion, following a stressor an individual may differ with regard to their psychological response to the event, and also whether they experience a cortisol increase. This may affect whether they are more distressed later on, and also whether they remember the event accurately.

How does immediate recall of a stressful event affect psychological response to it?

BACKGROUND AND OBJECTIVES

In forensic settings, individuals who experience a traumatic event are often encouraged to recall it soon afterwards to preserve their memory for it. Some theories of the development of post-traumatic stress disorder (PTSD) suggest that this may increase psychopathology. The primary aim of the study was to examine the effect of immediate recall of a trauma analogue video on psychopathology.

METHOD

Eighty-five undergraduate students were randomised to view a video of a car accident, described as either a real event (high stress) or training event (low stress). They then completed either the Self-Administered Interview (SAI©, Gabbert, Hope, & Fisher, 2009) or a filler task. All participants returned one week later to provide an account of the event.

RESULTS

As predicted, participants in the SAI early recall task condition remembered the video content better one week after seeing the video, shown both by their greater recall of correct details and greater rejection of misinformation. However, completing the SAI resulted in higher anxiety immediately afterwards, and more severe PTSD-like symptoms one week later, compared to control condition. PTSD intrusion-like symptoms also predicted more accurate recall, while avoidance predicted poorer memory.

LIMITATIONS

While the trauma analogue video used in this study has been previously used, and did effectively trigger post-traumatic-like symptoms, it is unclear how well these results generalise to actual trauma situations.

CONCLUSIONS

These results suggest the relationship between PTSD symptoms and memory might be more complex than previously recognised, with intrusive phenomena possibly promoting memory and avoidance symptoms compromising memory.