Investigators often have multiple suspects to interview in order to determine whether they are guilty or innocent of a crime. Nevertheless, co-offending has been significantly neglected within the deception detection literature. The current review is the first of its kind to discuss co-offending and the importance of examining the detection of deception within groups. Groups of suspects can be interviewed separately (individual interviewing) or simultaneously (collective interviewing) and these differing interviewing styles are assessed throughout the review. The review emphasizes the (...) differences between lone individuals and groups. It focuses on the theoretical implications of group deceit and the reasons why groups need to be understood in terms of investigative interviewing and deception detection if all types of crime-related incidents are to be recognized and dealt with appropriately. Group strategies, consistency within- and between-statements, joint memory, and group dynamics are referred to throughout the review and the importance of developing interview protocols specifically for groups is discussed. The review concludes by identifying the gaps in the literature and suggesting ideas for future research, highlighting that more research is required if we are to obtain a true understanding of the deception occurring within groups and how best to detect it. (shrink)

Deception has evolved to become a fundamental aspect of human interaction. Despite the prolonged efforts in many disciplines, there has been no definite finding of a univocally “deceptive” signal. This work proposes an approach to deception detection combining cognitive load manipulation and T-pattern methodology with the objective of: (a) testing the efficacy of dual task-procedure in enhancing differences between truth tellers and liars in a low-stakes situation; (b) exploring the efficacy of T-pattern methodology in discriminating truthful reports from deceitful ones (...) in a low-stakes situation; (c) setting the experimental design and procedure for following research. We manipulated cognitive load to enhance differences between truth tellers and liars, because of the low-stakes lies involved in our experiment. We conducted an experimental study with a convenience sample of 40 students. We carried out a first analysis on the behaviors’ frequencies coded through the observation software, using SPSS (22). The aim was to describe shape and characteristics of behavior’s distributions and explore differences between groups. Datasets were then analyzed with Theme 6.0 software which detects repeated patterns (T-patterns) of coded events (non-verbal behaviors) that regularly or irregularly occur within a period of observation. A descriptive analysis on T-pattern frequencies was carried out to explore differences between groups. An in-depth analysis on more complex patterns was performed to get qualitative information on the behavior structure expressed by the participants. Results show that the dual-task procedure enhances differences observed between liars and truth tellers with T-pattern methodology; moreover, T-pattern detection reveals a higher variety and complexity of behavior in truth tellers than in liars. These findings support the combination of cognitive load manipulation and T-pattern methodology for deception detection in low-stakes situations, suggesting the testing of directional hypothesis on a larger probabilistic sample of population. (shrink)