Facilitating episodic recall for repeated events: insights from a diverse range of professionals

To identify eligible participants, the authors relied on their professional networks and also contacted organizational representatives for assistance in identifying suitable people (e.g. public health departments). Invitations to participate were initiated via email and/or in-person. The primary eligibility criteria were that participants had to have been working in the relevant field for a minimum of 10 years or were recognized as highly skilled in their role, and had to conduct interviews regularly as a part of their professional duties.

In total, 16 professionals participated. Two potential participants declined, citing irrelevant experience. Thematic saturation - defined as the point at which no novel categories relevant to the primary research questions (i.e. strategies for eliciting episodic information) emerge and the information becomes repetitive (Urquhart, 2013) - was apparent after 16 interviews, so sampling was discontinued at this point.

The participants included medical professionals (a nurse consultant for quality and patient safety, a cardiologist, an infectious diseases doctor, a public health senior medical officer and a doctor of osteopathic medicine), legal professionals (a family and compensation lawyer and a corruptions investigator), law enforcement (a senior executive in corrective services, an investigator of war crimes, an investigator of events related to national security such as terrorism, a police detective), as well as a workplace investigator (e.g. bullying, harassment), an airline investigator (who interviews pilots to investigate their operating practices), a teacher who interviews children (e.g. playground incidents), an immunology laboratory manager who interviews staff and students when a routine procedure malfunctions, and a health coach who needs to understand clients’ lifestyle (e.g. nutrition, injuries). A brief description of each of these professions and their relevance to interviewing about repeated events is available at: www.osf.io/usjmk/?view_only=ead96b4def574d5cbf610a881d90f227. On average participants had 24.17 years of experience in their role (SD = 13.52, range = 3–46) ^[1]. Nine participants had not received interview training and seven had received some training.

Ethical approval for this study was granted by Griffith University’s Human Research Ethics Committee. The methodology is described in accordance with the consolidated criteria for reporting qualitative studies (COREQ, Tong et al., 2007); the complete checklist can be accessed at: www.osf.io/usjmk/?view_only=ead96b4def574d5cbf610a881d90f227

Participants were told that the purpose of the study was to understand what questioning techniques interviewers use to gather and distinguish details about specific episodes of a repeated event. Following informed consent, the professionals individually took part in an interview, which was either conducted face-to-face (n = 6) or over an online platform (n = 10), in accordance with participant preferences and practical considerations (i.e. location).

The interview commenced with basic background questions concerning their professional role and whether they had previously completed interviewing training. The rest of the interview focused on the following pre-planned prompts:

• Please provide an overview of the type of investigations that you conduct.

• Do you interview people as part of these investigations?

• What constitutes a good interview?

• Do you ever have to interview about an event that happened on more than one occasion?

• Do you ever have to isolate what happened on one occasion of that event as distinct from other occasions?

• (If yes) Please elaborate on the process as thoroughly as possible.

• What do you do if – when you ask the person to isolate an occurrence of a repeated event – they say they can’t remember. What happens next?

• How do you know if isolating one episode of a repeated event has been done successfully?

The interviews were centred around these core prompts, and followed a semi-structured format to enable the interviewer to flexibly encourage elaboration on topics raised by each professional.

On average the interviews were 39.86 min in duration (SD = 13.80, range = 19.98–71.43). All interviews were audio recorded and transcribed verbatim.

A ‘codebook’ approach to thematic analysis was utilized to analyse the data (Braun and Clarke, 2019). Codebook approaches provide a structured framework to guide the analysis, while also maintaining the flexibility inherent in qualitative analysis (Braun and Clarke, 2019). The analysis was also deductive, with codes and themes emerging from the data itself rather than being imposed by an existing theoretical framework. The analysis followed the six phases outlined by Braun and Clarke (2006).

The first phase of analysis involved data familiarization in which two researchers read the transcripts to gain an in-depth understanding of the data and noted salient themes. Next, the researchers coded recurring patterns, meanings and content in the transcripts. Relevant data were extracted and categorized in accordance with these codes. This second stage of analysis was iterative: While a preliminary list of codes and definitions was prepared before the outset of analysis (based on data familiarization), new codes were identified during the coding process, and these were added to the complete list of codes. When new codes were identified, relevant transcripts were revisited to thoroughly document all text that represented these categories of novel content and meaning. After the transcripts had been systematically coded in this way, themes and subthemes were identified based on comparing the similarities and differences between the codes.

The analysis was conducted by two researchers (SD and MP) and was highly collaborative. Prior to analysis, the two researchers read the transcripts, independently noted recurring patterns and themes, and subsequently discussed these themes. Next, SD systematically coded the transcripts following the process described above. Throughout this process, SD referred to extensive electronic notes compiled by MP concerning interpretation of the data and its relevance to the primary research questions. The researchers also discussed the emerging themes at multiple points throughout the analytic process. SD provided a summary and detailed description of the final themes, including representative quotes, to all authors, and the research team agreed on the final themes. These themes are detailed below, supported by de-identified quotes edited for readability.

Two overarching themes emerged. First, the professionals acknowledged the strengths and limitations of repeated-event memory. They considered these aspects of repeated-event memory in their approach to interviewing people about repeated events and identified various strategies to facilitate episodic recall, which we describe in Theme two.

The responses of most professionals reflected an awareness that interviewees typically have a strong memory for overarching event patterns but difficulty recalling details about specific episodes. The airline investigator (who interviews pilots about their procedures on a given flight to evaluate the appropriateness of standard operating procedures) noted that pilots are often good at providing information about general patterns in their routine, such as the aircraft type. In contrast, pilots struggle to recall specific episodic details, such as departure time. A topically similar example was provided by the workplace investigator:

The professionals observed that when people do recall individual episodes, different instances of the event often merge together, resulting in a blurred representation of both the overarching timeline and specific episodes. The professionals noticed this merging based on inconsistencies in the interviewees’ recall. The professionals also reflected on how interviewees frequently verbalize difficulties in remembering an episode of a repeated event:

There were commonalities in the strategies described by the professionals when aiming to elicit information from a specific episode, although not all professionals used the same techniques. Table 1 presents the list of strategies used by the group and indicates which professionals used each approach.

In addition to variation across professionals, several noted that they adapted their approach to each interviewee, based on the interviewee’s ability to recall the event (e.g. considering the level of detail and structure in their narrative) and psychosocial factors (e.g. stress).

The quality of information provided by the interviewee early in the interview often guided the approach taken by many professionals. For instance, several professionals noted that certain interviewees sequence accounts well, while others need additional structuring to present details coherently. Additionally, some interviewees initially offer a large amount of relevant information, whereas others require extensive memory-enhancing strategies, as explained by a senior executive in corrective services:

The professionals were aware of various strategies to facilitate episodic recall, including asking what usually happens and what was distinctive, using labels to refer to event occurrences, context reinstatement techniques, re-tracing the initial account to elicit further detail, providing information about the interview process, using external evidence as retrieval cues and constructing a timeline. In the following section, we describe each of these strategies.

When interviewees found it challenging to recall a specific episode, the professionals often jogged memory by focusing on the routine and the distinctive aspects of that occurrence. They indicated that inquiring about typical practices and habits could refresh the interviewee’s memory by establishing a familiar framework against which deviations or specific instances could be identified. By eliciting this generic information, the professionals hoped to trigger recollections of novel event episodes, noting that this often did occur.

Paired with the strategy of asking about usual routines, it was common for the professionals to inquire about what was distinctive about a given episode. To do so, many used prompts such as ‘what was unique?’ or ‘what stood out?’ regarding the episode of interest. For instance, the nurse investigator reflected on a case where a patient had been given an incorrect catheter that led to the patient’s death. To facilitate memory of the catheter used that day, the participant asked the interviewee, “Describe what you would normally do, and what do you think was different on this day when the event occurred”. Although it was common for the professionals to pair questions about routines and distinctive details together in this way, each strategy was also used independently.

The professionals were aware that incidents deviating from routine were especially well recalled, and that lack of distinctiveness can impair recall. The corrective services executive reflected on the monotony of prisoners’ lives, in terms of routine and the physical environment, making episodic recall particularly challenging for prisoners. Nevertheless, the executive still used the strategy of identifying distinctive elements, such as whether a prisoner received a visitor or medical treatment on the day of the episode of interest. Similarly, the corruptions investigator observed that interviewees often remember transactions which are perceived as particularly unusual relative to common practice:

Unique aspects of the event episode were perceived as cues to help the interviewee focus on that occurrence and facilitate retrieval of additional episodic details. The detective, for instance, constructed a list of known episodes of interest at the outset of the interview and then asked the interviewee to describe what was unique about each time. These distinctive details were used subsequently as a starting point to invite a narrative of each episode. Other professionals, such as the national security investigator, used similar strategies:

There was a widespread perception that episodes eliciting strong emotions were distinctive and these episodes were often reported with clarity. Consequently, many of the professionals aimed to identify occurrences that were especially emotional for the interviewee. The perceived value of eliciting emotions to facilitate episodic recall is highlighted by the following extract:

In addition to facilitating recall of the event itself, distinctive details were often highly relevant to the professionals’ investigations. For instance, when the cardiologist asked patients about distinctives (e.g. the time a patient experienced a blackout cycling), it could yield information explaining why the medical event occurred at that time (e.g. it was a very hot day). Relatedly, the health coach noted that identifying distinctive factors (e.g. high stress, poor sleep) could help explain why an injury occurred during a routine exercise at the gym.

Several professionals described using labels to refer to particular occurrences. Various approaches were used to creating labels, including temporal labels, which typically involved asking about the first or last time the event occurred. It was generally perceived that targeting recent (versus distant) episodes is an effective strategy since these episodes are typically better remembered. Some professionals used emotional labels like ‘the worst time’. For instance, the cardiologist asked patients about the worst blackout they had experienced. This type of prompt was considered effective because it allowed for the interviewee’s subjective interpretation of what constituted the ‘worst time’, and which episode emotionally affected them most. Labels were also created based on the content of the episode, and the professionals emphasized the importance of listening to the interviewee’s narrative and reusing the interviewee’s own phrases. Some of the professionals noted that labels derived from the content of the interviewee’s story (e.g. ‘the time he hit me’), are often more effective than temporal labels (e.g. the ‘first/last time’):

Many of the professionals recognized that encouraging the interviewee to focus on contextual characteristics surrounding the event would facilitate more detailed episodic recall. Thus, they adopted an approach that reflected context reinstatement ^[2], attempting to immerse the interviewee in the sensory details (e.g. sights, sounds and smells), affective state and context surrounding the episode, as illustrated by the health coach:

Professionals often encouraged interviewees to focus on external characteristics related to the event, such as locations, dates and the people involved. For instance, the nurse consultant tried to get the nurse interviewee to focus on the patients seen prior to the event of interest, as well as other nurses who were on shift the day of the event occurrence:

While many professionals oriented interviewees to general characteristics of the event occurrence, the detective noted the particular effectiveness of encouraging interviewees to focus on specific moments within an episode to facilitate recall (e.g. ‘You mentioned that the suspect pointed a gun at you. I want you to think back to that moment and describe it to me in as much detail as possible’).

The types of question that the professionals used when describing their context reinstatement approach varied in scope and specificity. While some were open-ended (e.g. ‘Concentrate on that event and tell me what happened in as much detail as possible’, detective), others were specific and/or leading (e.g. ‘Were you swimming? Were you in a car?’, osteopathic doctor), suggesting there was variation in how the professionals applied context reinstatement techniques.

Another method the professionals used to immerse the interviewee in the episode of interest was retracing the interviewees’ initial free narrative account and requesting further detail. Several professionals noted that this approach brought additional details to the interviewee’s awareness. While guiding the interviewee back through their account, the professionals often focused on details most relevant to their specific area of investigation. For instance, the health professionals typically concentrated on bodily sensations reflecting medical symptoms, while detectives and investigators focused on facts critical to the case (e.g. elements of the offence). Occasionally, this technique was also applied in follow-up interviews after the professional had obtained additional information about the investigation. In these follow-up interviews, interviewees were guided back through their account to encourage elaboration on details not previously recognized as relevant (e.g. results revealing a specific type of infection, or when key issues in a legal case became more clearly defined):

An additional strategy that the professionals used to elicit comprehensive information about the event was to provide clear information about the nature and purpose of the interview to interviewees. This strategy reflects a more general interviewing approach, not necessarily specific to the context of a repeated event. For instance, it included explaining the scope and topic of the interview, detailing the purpose of the questioning, clarifying how their information would be used (e.g. to identify system errors rather than attributing personal fault to the interviewee, nurse investigator). Additionally, many of the professionals naturally provided ground rules, such as assuring the interviewee that there was no right or wrong answer to their questions. Despite the broad applicability of this approach, the professionals perceived that well-defined interview expectations could enhance episodic recall as an additional benefit.

Several professionals also tailored their instructions specifically to the context of a repeated event. For instance, some professionals would explain to interviewees why information about specific episodes was necessary for the investigation, while recognizing the challenges inherent in doing so:

Other professionals tailored ground rules specifically to repeated events, informing the interviewee that it can be difficult to separate multiple incidents – as reflected in the prior quotes. These professionals also advised the interviewee to say if they could not remember what happened and not to fill in details they could not recall. Relatedly, some professionals attempted to clarify the success of particularization by asking questions, such as the interviewee’s confidence in the accuracy of their recall for the event, and whether they thought they were merging multiple occurrences together:

Most professionals indicated that they used external evidence to facilitate episodic recall, and for many of the professionals, these aids were generally available. The evidence utilized in interviews differed according to the professional’s field, and they included cell location trackers (infectious disease traces), electronic transactions (corruptions investigator), virtual meeting recordings (workplace investigator), patient charts (nurse), phone application-based flight logbooks (airline investigator), logbooks of laboratory procedures (laboratory manager), fitness trackers and food diaries (health coach) and the recall of other people (e.g. cardiologist, teacher). The professionals perceived that external evidence could trigger recall even when the information available through the resource was scant (e.g. flight logbooks typically contain minimal information, such as departure and arrival times):

The evidence used in interviews was primarily digital. Several professionals noted the increasing availability of digital evidence and predicted that artificial intelligence would soon enhance the accessibility of these resources. This changing landscape in the nature of investigations was noted by the corruptions investigator:

There were commonalities in how the professionals introduced evidence, with most doing so after first attempting to elicit the interviewee’s narrative. When interviewees were unable to remember the episode, however, the professionals often used evidence as a starting point to prompt memory.

In addition to being used as retrieval cues, evidence was used to support the investigation; in fact, the professionals often relied on physical evidence more heavily than memory accounts due to an awareness of the fallibility of memory, especially when dealing with repeated events. They thus prioritized evidence that could provide a clear and objective record of the event rather than relying on memory and perceptions which they considered unreliable, especially given that repetition creates confusion. The professionals used external records to cross-check narratives and clarify details, helping to piece together the information:

Finally, some of the professionals used a timeline as a tool to direct their questioning about repeated events. For most of the professionals who mentioned using this approach, the timeline was a tool for the interviewer rather than for the interviewee, since it helped the interviewers to direct their line of questioning. This approach entailed the interviewer writing a list of different event episodes of interest, organizing these episodes chronologically and listing associated details for each event. During questioning, the interviewer subsequently focused on each episode at a time. The infectious disease tracers created timelines that tracked interviewees’ movements day by day over a two-week period, working backwards in time. Several professionals noted that this approach helped them to identify gaps or inconsistencies in the interviewee’s account, such as when the interviewee appeared to mix up details across occurrences.

One professional (i.e. the detective) used the timeline approach in collaboration with the interviewee. The detective would write all known episodes of interest on a piece of paper or whiteboard for the interviewee, perceiving that this strategy facilitated recall and helped prevent the merging of episodes. Even when not using a concrete (written) timeline, most of the professionals aimed to establish the sequence of events over time for the purpose of the investigation, as reflected by the war crimes investigator:

The experienced professionals in the current study used various strategies to facilitate episodic recall that align with current evidence-based recommendations. These strategies included choosing clear labels for occurrences, asking about both distinctive episodes and general event information, providing information about the purpose of the interview, mentally reinstating the context of an episode and re-tracing the initial account to elicit further details (Brubacher and Earhart, 2019; Brubacher et al., 2014; Fisher and Geiselman, 2010; Powell and Snow, 2007). It appears that, through the course of trial and error across their extensive professional experiences, the professionals independently developed techniques that generally mirror recommendations derived from psychological laboratory research.

Despite their clear insights into what could be effective, there was room for refinement in the strategies utilized by the professionals. For instance, their descriptions implied an overreliance on specific and leading questions, which are likely to restrain response accuracy compared to open-ended prompts–the latter being considered best-practice (Vrij et al., 2014). Moreover, individual professionals mentioned only a few of the strategies from the broader set of techniques collectively used by the group. These considerations suggest that experienced practitioners could benefit from expanding their interviewing techniques (Powell et al., 2014). Nonetheless, the fact that many of these strategies were generally consistent with evidence-based recommendations is notable and underscores the value of integrating practitioners’ knowledge and perspectives into research.

The professionals highlighted several techniques that have been under-explored in repeated-event research, particularly the use of external evidence as retrieval cues. While further research on this technique is needed, preliminary findings indicate that context-specific cues can facilitate episodic recall (Willén et al., 2015). When 95 adults were asked to list and describe different occurrences of a routine event (dental visits), participants given derived cues–based on what a pilot sample recalled as memorable about their own dental visits- displayed various recall advantages. Specifically, they listed more visits and described visits in greater detail with no detriments to accuracy, compared to participants prompted with cues typically used in police practice (Willén et al., 2015). Hence, providing context-specific information through external evidence may enhance episodic recall (see also Leins et al., 2014).

The types of external evidence used by the professionals varied in the amount of additional information they introduced to the interview process. Some forms of evidence introduced limited information, such as flight times and locations logged in pilots’ digital logbook. Others, like the recollections of additional witnesses, introduced greater quantities of information about the occurrence. The suitability of introducing external evidence and the choice of which forms to use may depend on the investigative context and the standard of proof required, with a need to balance the risk of memory contamination alongside potential retrieval benefits.

To date, applied repeated-event research has been shaped largely by legal considerations and the evidentiary requirements of relevant offences (e.g. child sexual assault cases). In this context, the high standard of proof means that introducing external evidence could compromise the complainant’s evidence and credibility (Newlin et al., 2015). Moreover, external evidence is also often unavailable in such cases (e.g. Powell et al., 2007). In professional contexts where repeated-event interviews are routine and the standard of proof is lower, external evidence may play a valuable role in enhancing episodic recall. This underscores an important consideration for researchers: A narrow and specialized research focus may inadvertently limit the relevance of research findings, while a broader focus could lead to insights applicable to multiple areas of the criminal justice system and beyond (Fisher, 2014).

Nonetheless, in contexts where the burden of proof is high, such as corruption and family law investigations, self-generated cues may need to be prioritized. For instance, many of the professionals intuitively applied strategies resembling mental context reinstatement techniques. The retrieval benefits of this practice for single events are well-established (Smith and Vela, 2001), and preliminary research indicates the potential of this strategy for repeated events as well. When mental context reinstatement is used alongside additional memory strategies–namely those embedded in the Cognitive Interview–participants tend to list more occurrences of an experienced event, provide more detailed descriptions of those occurrences and are less likely to report details that are schematically consistent with the event but were not experienced, compared to standard interviewing procedures (Goldfarb et al., 2023; Leins et al., 2014; Rivard et al., 2014). These benefits have been demonstrated in the field: when interviewees involved in repeated terror-related events in Israel were interviewed using the Cognitive Interview, they were able to recall novel event instances they had not previously recalled in multiple prior standard interviews, and the accuracy of the novel information was supported by high corroboration rates with external evidence (Ashkenazi and Fisher, 2024).

Only one study has examined the independent impact of mental context reinstatement on adults’ recall of a repeated event, finding that while context reinstatement did not enhance memory for central event details, it did enhance reporting of contextual details surrounding occurrences and the overarching event (Sharman et al., 2022). Hence, when used as a standalone technique, context reinstatement procedures may need to be refined to target episodic rather than schematic recall, such as orienting interviewees to salient aspects of specific episodes, as noted by the detective in the current study.

Emerging research points to the efficacy of additional memory strategies that leverage self-generated cues to facilitate episodic recall. The timeline technique, for example, is a physical tool designed to help interviewees visually sequence an event. This approach has been found effective in helping adult interviewees recall details about repeated events when used independently (Hope et al., 2019) and in combination with other memory strategies (Kontogianni et al., 2021), without a reduction in overall accuracy. There is some evidence, however, that it may be problematic for interviews with children about repeated events (Zhang et al., 2019). In the current study, most professionals used a timeline to organize their questioning. Exploring the utility of the timeline approach for interviewers, as well as extending research on the efficacy of this strategy for interviewees, will likely be valuable lines of research, with particular applicability in investigative contexts where the burden of proof is high.

Going forward, it is important for research to further explore the effects of memory strategies and external evidence on episodic recall. The findings of the current study indicate that the use of external evidence as recall cues–particularly in digital formats–could be increasingly prevalent in the field. Considering ongoing technological advancements, these forms of evidence are likely to become even more prevalent for interviewers across various professional fields and are thus important to prioritize in future research.

The current study examined professionals’ descriptions of their approach to eliciting information about repeated events to gain rich insights into their perspectives on this process. Since we did not analyse field interviews conducted by the professionals, it is unclear to what extent they actually utilized these strategies in their personal practice. Such information would be valuable. The analysis of field transcripts could provide more objective data on the strategies that professionals use. Relatedly, we did not objectively measure the participants’ skills in interviewing; our sample comprised professionals with extensive experience in their role. Although experience and skill are not necessarily correlated by every measure (e.g. Powell et al., 2014), we took the perspective that the professionals had likely developed unique investigative techniques and insights throughout their careers that might be overlooked by conventional measures of questioning skill, such as adherence to open-ended questions. These conventional measures may even have limited relevance in certain professional roles. Instead, we aimed to learn from the professionals, exploring their insights to enrich our understanding on interviewing about repeated events. Indeed, while relying solely on formal empirical research risks limiting the relevance and utility of findings on a given topic, drawing on diverse sources of information, such as the experiences of frontline professionals, can offer a broader and more innovative perspective (Fisher, 2014).

Repeated-event research has been conducted primarily with a focus on the requirements of relevant legal offenses. However, the professionals involved in the current study highlighted how repeated-event interviewing is relevant to a variety of disciplines, both in the legal field (e.g. corrections, corruptions investigations) and beyond (e.g. airline investigations). The professionals involved used strategies that were broadly consistent with current evidence-based recommendations. However, as each professional reported only a few strategies from the broader set of techniques collectively used by the group, they may benefit from expanding their interviewing techniques. Their strategies also included techniques that have been under-explored in current research, such as the use of external evidence as retrieval cues. Research into these strategies would be valuable to maximize the applicability of repeated-event research across diverse disciplines.

Funding: Australian Research Council: DP230101634.