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Does Active Response vs. Observer Role Impact Officer Recall of Firearms Encounters?

Forensic Training AcademyA recent study in the United Kingdom suggests accurate recall of details in firearms encounters may decrease when police officers have an active role in the encounter. This is the bottom line of a recently published article in Law and Human Behavior. Below is a summary of the research and findings as well as a translation of this research into practice.


Law and Human Behavior Featured Article | Law and Human Behavior | 2016, Vol. 40, No. 1, 23-35


Memory and the Operational Witness: Police Officer Recall of Firearms Encounters as a Function of Active Response Role


Lorraine Hope, University of Portsmouth
David Blocksidge, Metropolice Police, London, United Kingdom
Fiona Gabbert, Goldsmiths, University of London
Arta Mirashi, Universty of Portsmouth
Emel Atuk, University of Portsmouth


Investigations after critical events often depend on accurate and detailed recall accounts from operational witnesses (e.g., law enforcement officers, military personnel, and emergency responders). However, the challenging, and often stressful, nature of such events, together with the cognitive demands imposed on operational witnesses as a function of their active role, may impair subsequent recall. We compared the recall performance of operational active witnesses with that of nonoperational observer witnesses for a challenging simulated scenario involving an armed perpetrator. Seventy-six police officers participated in pairs. In each pair, 1 officer (active witness) was armed and instructed to respond to the scenario as they would in an operational setting, while the other (observer witness) was instructed to simply observe the scenario. All officers then completed free reports and responded to closed questions. Active witnesses showed a pattern of heart rate activity consistent with an increased stress response during the event, and subsequently reported significantly fewer correct details about the critical phase of the scenario. The level of stress experienced during the scenario mediated the effect of officer role on memory performance. Across the sample, almost one-fifth of officers reported that the perpetrator had pointed a weapon at them although the weapon had remained in the waistband of the perpetrator’s trousers throughout the critical phase of the encounter. These findings highlight the need for investigator awareness of both the impact of operational involvement and stress-related effects on memory for ostensibly salient details, and reflect the importance of careful and ethical information elicitation techniques.


eyewitness memory, stress, arousal, law enforcement, interviewing

Summary of the Research

“Law enforcement officers, military personnel, and others in civil or emergency response occupations are frequently involved in dynamic, challenging incidents. Depending on their particular operational mandate, these “operational witnesses” may need to act to preserve life, protect citizens, neutralize threats, initiate recovery, or engage in some combination of related activities to resolve an incident. Accurate and detailed accounts of the incident, and information about the operational witness’s own activities and that of colleagues, may be important for subsequent investigations and the eventual delivery of justice” (p. 23). “The current research examined the effects of active involvement on eyewitness recall memory. We compared the recall performance of operationally active witnesses responding to a (simulated) threatening incident with that of nonoperational witnesses, or bystanders, to the same event; hereafter referred to as active and observer witnesses, respectively” (p. 23).

“First, we examined whether there were differences in the accounts provided by operational (active) and nonoperational (observer) witnesses where both had been exposed to the same incident. To achieve this we put pairs of police officers into an immersive and stressful simulated scenario where one officer was instructed to respond as they would usually in the course of their duty (i.e., an active operational witness) while the other was instructed to simply observe the scenario. To our knowledge, this is the first study to adopt a methodology of this kind to examine the effects of active role involvement in an eyewitness context. We predicted that officers allocated to the active response role would show an increased physiological response in the scenario, reflecting by proxy, increased stress as a function of their active response role. On the grounds of this increased arousal, and consistent with the theoretical accounts outlined above, we predicted that the quality and quantity of free recall reported by the active response officers would be impaired relative to the observers” (p. 25). “In addition to the free-recall task, both witnesses were asked a series of detailed closed questions. These questions were included to contribute data and inform current practice and policy in the investigation of shooting incidents” (p. 25). “We were particularly interested in the recall performance of active witnesses (relative to their observing cowitnesses) on questions pertaining to use and location of the target’s weapon as such questions are, unsurprisingly, a central focus of investigations following police shootings. Specifically, we predicted that additional demands on the resources of operational witnesses in conjunction with higher arousal and stress levels, both likely to occur when police officers were required to discharge (or consider discharging) their own weapon, would impair recall for such information” (p. 25).

“Our second independent research question concerned the possible effect of expectations as they relate to memory performance under challenging operational conditions. Deliberately, the scenario was designed to trigger schema-driven expectations regarding the likely action of the perpetrator. In the final sequence of the scenario, the perpetrator who was at this point known to be armed, turned quickly to face the officers, throwing out his hands in front of him. However, the weapon (a gun) remained in the waistband of his trousers. In light of the memory deficits reported in previous research and well-documented effects of schema-reliance, we predicted that memory reports provided by officers in the Active (cf. Observer) condition may be particularly vulnerable to the expectation-based error that the perpetrator would point the weapon at them” (p. 26).

Officers were paired and then randomly assigned to either the “Active Officer” or “Observer Officer” role. All participants viewed a briefing video that depicted a hostage-taking incident, where an angry student took a professor and another student hostage with a knife. “The Active Officer was provided with a training handgun loaded with five blank rounds (i.e., their weapon was available for discharge) and informed s/he was part of an initial response team with the objective of moving forward into the classroom adjacent to the corridor containing the hostages to tactically assess the situation and intervene, or advise other teams available to intervene as necessary. Before entering the critical response phase, both participants, seated side by side, viewed the briefing video on a laptop screen. They were told that this was “cell phone footage that a witness captured as the situation developed this morning.” This concluded the briefing phase. At the outset of the critical response phase, both officers were then taken into the classroom where they could view the live CCTV footage of the ongoing incident” (p. 27). They proceeded to encounter an “ ‘augmented reality’ scenario, lasting 4 min, which incorporated prerecorded and live elements. The prerecorded elements of the incident were presented as “live” CCTV footage and were integrated with fully scripted, tightly controlled live elements, reenacted for each pair of participants, using three actors (one male “perpetrator,” two male “hostages”). At the outset, the perpetrator was shown via a CCTV-feed, threatening the two hostages in a hallway (outside the classroom where they had originally been located in the briefing video). One of the hostages was then released and could be seen walking down a hallway, appearing first in the “CCTV footage” and then in reality through a window in the classroom through to the same hallway… the perpetrator then entered the classroom (where the officer participants were located) using a hostage as a shield and holding a knife to the hostage’s neck. After issuing various demands, he set the hostage free and threw the knife to the ground before retreating to the hallway and closing the door to the classroom. He could then be seen, on the CCTV, tucking the gun into the waistband of his jeans. In the final live interaction, the perpetrator reentered the classroom in an agitated manner. The gun remained in the waistband of his trousers throughout” (p. 26). All participants then provided a free recall and answered closed questions about the incident.

There were no significant differences between operationally active witnesses and observer witness regarding the initial briefing video, which suggests that all participants, regardless of role, had a similar baseline for recall of events. “However, an interesting difference emerged between active and observer officers in their recall of the critical response phase. Operationally active witnesses reported significantly fewer correct details about the scenario than observer witnesses. However, there were no differences, according to role type, in the overall accuracy rate of information reported. Thus, operational witnesses, in free- recall tasks at least, were able to sustain the accuracy of their accounts. Indeed, accuracy rates for freely reported information were very high across both operational and nonoperational witnesses (>92%)” (p. 30). “Operationally active witnesses showed significantly higher levels of physiological arousal, as marked by higher HRs and lower HRV, during the critical response phase of the scenario in comparison with their nonoperational counterparts. It is noteworthy that significantly different HR measures were recorded for active witnesses despite the fact that officers in both active and observer roles were exposed to the same critical scenario and stood side by side while the scenario unfolded. In other words, higher HRs and lower HRV did not reflect increased physical activity—in fact, we deliberately limited the potential for differential physical movement through the enforcement of predetermined containment positions. Therefore, active witnesses in the current study experienced higher levels of physiological arousal or stress response as a function of the demands of their operational response role. Mediational analyses revealed that the observed effects of role on free recall performance were related to level of stress, as indexed by the maximum HR recorded during the critical response phase. Thus, while it is important to consider the role of a witness to an event, the degree of arousal experienced is also an important factor” (p. 30).

Translating Research into Practice

“These are important findings and, to our knowledge, this is the first study to document a physiological difference between witnesses who have different roles in responding to the same incident, observe that the effect of role operates through an arousal mechanism and demonstrate differences in memory performance for operational versus nonoperational witnesses. As such, these findings confirm the merits of considering the role of “operational witness” when evaluating their statements” (p. 31). “Examination of the errors made by active witnesses in response to closed questioning highlights particular areas of vulnerability in their recollection of the incident. Specifically, as illustrated by performance on target questions, the recall performance of active witnesses was significantly impaired, relative to observer officers, for critical information about the weapon in the final moments of their interaction with the perpetrator (i.e., when threat level was greatest). Active witnesses reported less information than observers in response to questions about the weapon and their responses were less accurate. Active officers were also more likely than their observer counterparts to categorize their use of a Do Not Know response as “I did not report an answer because the information was not present in the event”. This suggests that details of the event were either not encoded in the first place or were no longer accessible” (p. 31).

It would be important for practitioners who interview officers involved in these incidents (i.e., psychologists, other law enforcement personnel, legal professionals) to consider these findings by interviewing the active officer separately from any other observer witnesses. Separate interviews would allow for a comparison of recalled memories of the event, and the findings of the research should be considered when discrepancies arise. Additionally, considering the recent frequency of police misconduct allegations and accusations of excessive force in the United States, the research described here should alert the psychological and legal communities to the necessity of careful and ethical techniques when it comes to eliciting information from officers involved in high stakes situations. The apparent ability of officers in this study to recall a fair amount of detail despite having been under pressure should suggest that suggestive interviewing and aggressive questioning of officers may be unnecessary. However, a higher stress response and a lesser ability to recall accurate details than their observer counterparts could explain why the details of reported events may differ between actively involved officers and other witnesses.

Other Interesting Tidbits for Researchers and Clinicians

“Through examining the performance of witnesses who, by virtue of their duty, are required not only to witness but also to react and respond under stressful conditions, the current research constitutes an important and timely contribution both to the psychological literature and wider policy concerns in legal and investigative contexts. To date, little research has systematically examined the recall of officers for challenging or threatening operational incidents, particular those involving use of lethal force. However, the investigation of such incidents constitutes a major and high profile task both for police forces and external agencies… Internationally, such investigations are typically high profile, attracting both public and media attention, and have serious consequences for the officers involved. Thus, the development of evidence-based policy and investigative practice is critical. The current results document the vulnerability of memory in this context and highlight the need for well-informed approaches to eliciting information from operationally active witnesses” (p. 32-33).

Join the Discussion

As always, please join the discussion below if you have thoughts or comments to add!

Authored by Marissa Zappala

Marissa ZappalaMarissa Zappala is currently a second-year Master’s student in the Forensic Psychology program at John Jay College of Criminal Justice in New York. Her main research interests include cognitive biases, forensic assessment, and evaluator training and education. Following her Master’s, Marissa plans to pursue a doctoral degree in clinical psychology and an eventual career in psychological assessment.

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