The focus of the majority of academic research has been the confidence of Police officers in high stakes lie detection when, for example, investigating murders, organized group operations and various street level crimes.
There has not been much focus on private sector investigators. Moreover, research have not focused on lie detection methods used by various investigative interview techniques.
This research will seek to explore the level of confidence of private sector investigators when it comes to such lie detection during investigative interviews and what type of training in lie detection increases their levels of confidence.
This research project is based upon two methods of analysis.
The first method is the critical literature review that discusses main ideas and arguments related to lie detection concepts in existing literature (https://www.cwauthors.com/article/difference betweenliterature-review-and-critical-review).
The second method is the online survey method that aims to describe aspects and characteristics of private sector investigators linked to the investigative interviews techniques and lie detection(https://research-methodology.net/research-methods/surveymethod/).
The research initially obtained 15 online survey answers related to the investigative interview techniques used and area of lie detection confidence and accuracy.
13 out of 15 respondents mentioned the Wicklander Zulawski Non-Confrontational Technique (WZ) and 2 mentioned the REID Technique. Based upon the assumption that these are the most common investigative interview techniques utilized in the private sector for investigations, these investigative interview techniques were used as a main input for the later critical literature review, its research validation and contrast with existing academic research in the area of lie detection (Brennen and Magnussen, 2022).
The research found that WZ and REID have similar approaches in lie detection and are based on similar research.
In particular the area of evaluation of subject’s behavior including verbal, non-verbal and para-linguistic (speech characteristics) behavior analysis. In addition, both are also using a specialized investigative interview method that asks specific behavior provoking and investigative questions with the aim of triggering the subject’s responses for analysis (Inbau et al, 2023 and Zulawski and Wicklander, 2002).
The research found out that there is a difference between practice in the real-world environment and what academic research say about lie detection. Academic research relies heavily on laboratory experiments with limitation on external validity (Horvath, Blair and Buckley, 2008).
The results of these studies may not accurately reflect what happens in the real world. On the other side, practitioners tend to most heavily rely on their own experiences as well as on instructional manuals and books, that have limited theory or research-based content (Horvath, Blair and Buckley, 2008).
Interestingly, the research conducted for this project report suggests a lack of confidence on the part of such practitioners.
Out of 16 online respondents’ majority of investigators rated lie detection accuracy between 20%-40% (6), and only 2 between above 80%. In addition, 6 respondents answered that their perceived level of confidence of applying lie detection skills if confident and 3 answered not at all confident.
Finally, 4 respondents answer that self-study is how they derived lie detection skills, 4 answers on-job training and 6 answers previous law-enforcement experiences.
Therefore, private sector investigators are not very confident in applying the lie detection skills that are mainly obtained through self-study or previous law enforcement experiences.
This is clearly visible in different approaches on evaluation of subject’s behavior which is not aligned with academic research and practitioners in some cases use old and sometimes nonvalidated methods such as eye movement (Brennen and Magnussen, 2022; Granhag and Vrij, 2010).
