The effects of cognitive load for investigative interviewers

  • Pamela Hanway

Student thesis: Doctoral Thesis


Conducting an investigative interview is cognitively demanding but there is a paucity of research that has examined the effects of cognitive load for interviewers. The overarching aim of the current doctoral research programme was to understand the cognitive processes of interviewing and how cognitive load for interviewers may impact upon their performance. Across five studies, this thesis explored investigative interviewers’ experiences of cognitive load and tested the effects of cognitive load on their performance.
The first investigation (Chapter 2), a field study, used an Interpretive Phenomenological Approach (IPA) to analyse investigative interviewers’ experiences when conducting interviews with children using the Achieving Best Evidence (ABE) guidelines (Ministry of Justice, 2011). Interviewers described factors that contributed to perceived demands, including overarching cognitive processes, such as remembering information and making judgements, and specific factors, such as the emotionality of a case. Interviewers also described the consequences and impact of cognitive load (e.g., forgetting information and being physically and mentally exhausted after interviewing). The first experimental laboratory research (Chapter 3) examined the effects of increased cognitive demands on mock-interviewers’ perceived cognitive load (PCL), and their recall of information. Under high, moderate, or low cognitive load conditions, participants watched the free narrative of a child witness. Participants in the high and moderate cognitive load conditions reported higher PCL and were less accurate in their recall of the witness’s account, than those in the low cognitive load condition. Experimental laboratory study 2 (Chapter 4) examined the effects of cognitive load (high or low cognitive load) on the accuracy of interviewers’ memory for information given by five witnesses, and their accuracy for monitoring the source of information,
provided by the multiple witnesses. Participants watched the free narratives of the five witnesses. The witnesses described the same crime, but each witness provided unique details about what they had seen. PCL was higher, and the accuracy of participants’ memory for the information provided by the witnesses was lower, in the high cognitive load condition than in the low cognitive load condition. Monitoring the source of information was challenging for all participants, regardless of cognitive load condition. The third experimental laboratory study (Chapter 5) explored the effects of note taking on participants’ perceived cognitive load and their recall of information given by a witness. The moderating effects of Working Memory Capacity (WMC) and access to notes at recall were also examined. Participants took free notes or structured notes and, during the recall task, they either had access, or not, to their notes. There was also a control condition of no note taking. When taking structured notes, with access to notes at recall, participants’ free- and cued-recall was more accurate, than it was for those who took free notes and for those who did not take notes, regardless of their WMC level. WMC and access to notes were moderators of PCL at recall. Finally, Chapter 6 explored, via an online survey, police officers’ PCL for different types of interview (i.e., interviews with victims using the ABE guidelines versus interviews with suspects using the PEACE model), for both serious (e.g., rape) and less serious (e.g., theft) crimes. Police officers indicated that they believe cognitive demands are higher when they interview for serious crimes than when they interview for less serious crimes. PCL was rated as higher when police officers conduct an interview with a witness using ABE guidelines than when they conduct an interview with a suspect.Taken together, this series of results showed that investigative interviewing is cognitively demanding. Factors that contribute to interviewers’ cognitive load were identified and when interviewers experienced cognitive load there was a negative impact on their recall of the information provided by witnesses. Techniques, such as taking structured notes, as well as interviewers’ WMC, may moderate the effects of cognitive load on recall accuracy. Implications of this programme of research for investigative interviewers are considered, and options for additional research suggested, in the general discussion of the thesis (Chapter 7).
Date of AwardDec 2020
Original languageEnglish
SupervisorLucy Akehurst (Supervisor), Zarah Vernham (Supervisor) & Lorraine Hope (Supervisor)

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