Unveiling faking in job interviews by examining facial thermal cues in deception detection

Detecting deceptive information in job interviews is a major challenge for improving personnel selection validity. Traditional interviewer-based methods for detecting applicant faking are limited in accuracy, highlighting the need for reliable techniques to enhance detection and minimize suboptimal hiring decisions. This study aimed to (a) investigate functional infrared thermal imaging (fITI), a non-invasive method for measuring facial temperature, to determine whether cognitive load and arousal during direct deception induce facial thermal changes indicative of faking; and to (b) develop an automated framework for processing infrared recordings, accounting for head movements and physiognomic differences. A within-person experimental design was conducted with 27 participants in simulated job interviews under five conditions: baseline, rehearsed truth, rehearsed lie, spontaneous truth, and spontaneous lie. A high-sensitivity infrared camera recorded thermal changes on the nose, forehead, and cheeks. Our dynamic feature extraction approach enabled robust temporal analysis despite naturalistic head movements. Linear mixed-effects models revealed no significant overall effect of faking; however, rehearsal and interaction effects were significant. Nasal temperature was higher in rehearsed than spontaneous responses and in spontaneous lies than spontaneous truths, while forehead and cheeks temperatures remained stable. Findings suggest that cognitive load from rehearsed and spontaneous questioning influences nasal thermal changes during faking.