Psychophysiological detection of concealed information shared by groups: An empirical study of the searching CIT.

Abstract

This study focused on the application of the Concealed Information Test (CIT) to situations in which the crime-related information is shared by a group of suspects but is not available to the investigators (a method known as the "searching CIT," or SCIT). Twenty-two groups, each comprising 4 to 7 participants (115 in total), planned 1 of 2 mock crimes (kidnapping or bank robbery). While planning the crime, each group decided on 5 crime-related critical items (e.g., the city in which the bank was located). Each critical item was chosen from a predefined set of 4 alternatives. At a second stage, the SCIT was administered individually and each participant was tested on the 2 crimes-the actual planned crime, in which the participant was "guilty," and the unplanned crime, in which the participant was "innocent." Two algorithms, adopted from Breska, Ben-Shakhar, and Gronau (2012), were applied to detect the critical items and to differentiate between "guilty" and "innocent" participants. Findings revealed that differentiation efficiency based on electrodermal and respiration measures was identical to that obtained with the standard CIT when applied to large groups, but lower, although significantly greater than chance, when applied to differentiate between small groups.