This dissertation investigates the validity of non-invasive methods for deception detection using functional infrared thermal imaging (fITI), remote photoplethysmography (rPPG), facial expression analysis, and eye-tracking. A case study (N = 1), two pilot studies (N1 = 15; N2 = 27) and a main experiment (N 100) explored deception under different levels of cognitive load (spontaneous vs. rehearsed), veracity (truth vs. lie), and interactions (all conditions including baseline) with attention to moderating role of attachment avoidance. To improve methodological precision, two automated systems for processing thermal data were developed. The results showed an increased heart rate during deception, especially during spontaneous lying, while facial temperature and gaze patterns reflected general task-related demands not deception per se. Emotional valence and arousal varied according to cognitive load, with greater engagement during spontaneous responses. Attachment avoidance moderated physiological responses and gaze behaviour, but not emotional arousal or valence. These findings challenge the notion of universal deception cues and support a context-sensitive, person-centred approach based on individual characteristics and situational factors.This dissertation investigates the validity of non-invasive methods for deception detection using functional infrared thermal imaging (fITI), remote photoplethysmography (rPPG), facial expression analysis, and eye-tracking. A case study (N = 1), two pilot studies (N1 = 15; N2 = 27) and a main experiment (N 100) explored deception under different levels of cognitive load (spontaneous vs. rehearsed), veracity (truth vs. lie), and interactions (all conditions including baseline) with attention to moderating role of attachment avoidance. To improve methodological precision, two automated systems for processing thermal data were developed. The results showed an increased heart rate during deception, especially during spontaneous lying, while facial temperature and gaze patterns reflected general task-related demands not deception per se. Emotional valence and arousal varied according to cognitive load, with greater engagement during spontaneous responses. Attachment avoidance moderated physiological responses and gaze behaviour, but not emotional arousal or valence. These findings challenge the notion of universal deception cues and support a context-sensitive, person-centred approach based on individual characteristics and situational factors.