SCANning for truth. Scholars’ and practitioners’ perceptions on the use(fulness) of Scientific Content Analysis in detecting deception during police interviews

ABSTRACT

SCAN (Scientific Content Analysis) is a verbal credibility assessment (VCA) tool that claims to detect deception in written statements. Although the validity of SCAN is contested in literature, various (law enforcement) agencies across the globe are trained in using SCAN. To date it remains unknown how SCAN is perceived, and to what extent it is used in practice. Based on a scoping review and qualitative survey, we identified practitioners’ and scholars’ perceptions on the use(fulness) of SCAN. Data were collected from 48 participants (35 practitioners and 13 scholars). Key findings illuminate (1) that practitioners apply an incomplete, personalized version of SCAN, (2) that SCAN practitioners are reluctant to abandon SCAN, and (3) that SCAN is considered incompatible with (Belgian) legislation on police questioning. Based on practitioners’ expressed needs and concerns, we present several alternatives for SCAN, as well as recommendations on how a shift to other techniques can be facilitated.

KEYWORDS:

• credibility assessment
• deception detection
• lie detection
• investigative interviewing
• interrogation

Acknowledgments

The authors would like to acknowledge the Belgian Centre for Policing and Security (CPS) for their collaboration. We would also like to express gratitude to the research participants for taking part in this study. We would also like to thank the reviewers for their extensive and valuable comments. The authors have reported all measures, conditions, data exclusions, and how they determined their sample sizes. The authors have no other related studies (including pilot tests) to report.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data is not available due to ethical restrictions. Participants of this study did not provide consent for their data to be shared publicly, so supporting data is not available.

Notes

1 For a more detailed explanation of these techniques, see Vrij et al. (2022) and Oberlader et al. (2020).

2 The following overview of the literature was obtained through a scoping review, of which the research protocol can be found in Appendix 1.

3 Deception and lying are often used as synonyms, but when considering SCAN the distinction between both is often emphasized. According to Vrij (2008, p. 15) deception can be defined as ‘a successful or unsuccessful deliberate attempt, without forewarning, to create in another a belief which the communicator considers to be untrue’. As such, there is a clear intent to conceal/withhold information and to mislead the receiver of the information, whereas lying can be considered as intentionally providing a false statement, of which the receiver might either be (un)aware that a lie is being told (for a detailed analysis, see Vrij (2008)). In this regard, lying can be considered as being a specific form of deception.

4 ‘Affinity’ refers to a connection with Belgium or the Netherlands through work and/or research (collaboration(s)).

5 This research was conducted in collaboration with CPS (https://www.policingandsecurity.be/). To our knowledge, CPS is the only organisation that offers SCAN training in Belgium.

6 For a more detailed explanation of the Belgian legislation in this regard, see Mergaerts and Dehaghani (2020). Suspects are entitled to consult with a lawyer prior to police questioning and are allowed to be assisted by a lawyer during police questioning as well (Article 47bis Belgian Code of Criminal Procedure and Article 2bis Belgian Pre-trial detention Act).

7 Seven academics identified as complete experts on SCAN, fully aware of SCAN’s literature, content, and method. Four academics identified as semi experts on SCAN, fully aware of SCAN’s literature, or SCAN’s content and method. Only two academics indicated they have notions of SCAN, as such they are familiar with SCAN but are no experts. The number of experts thus consists of eleven academics.

8 The demographics of the academic population are not known. We surveyed academics as a way of comparison. We therefore used a non-random homogeneous purposive sampling method based on two inclusion criteria to select academics and stopped when saturation was reached. It was thus not our intention to collect a representative sample of academics.

9 The questionnaires were reviewed by the supervisors of the project and external experts, both from practice and academia. These reviewers were also contacted to fill out the questionnaires. Whether or not those reviewers filled out the questionnaires is not known due to anonymity.

10 For a more detailed explanation of these techniques, see Vrij et al. (2022) and Oberlader et al. (2020).

11 For a more detailed overview of the content and method of these techniques and a discussion of their added value for practice, see Vrij et al. (2022).

Additional information

Funding

Isabo Goormans’ contribution to this work was supported by the Research Foundation Flanders [1114422N].