Cognitive mechanisms to detect deception: behavioural and brain stimulation evidence

Deception detection is a complex decision-making process, and detecting deception about opinions is important for applied contexts, such as security and defence policies. As the underlying neurocognitive mechanisms to detect deceitful opinions are not fully understood yet, the present work aims at providing novel behavioural and brain stimulation evidence across 5 studies. In Study 1, we show that the inconsistency effect (i.e., diminished deception detection accuracy when judges and actors hold inconsistent opinions about a topic) also extends to the justification of the opinions (i.e., experiential and ideological). In Study 2, we disentangle the differential role of opinion and justification statements in shaping the decision-making process, by adopting a dynamic decision-making approach. Moreover, in Study 3, we summarize the existing literature on psychophysiological indexes associated with the detection of deception by presenting a systematic review. On this basis, by applying Transcranial Magnetic Stimulation on the right TemporoParietal Junction, Study 4 shows its specific role in deception detection processes. Finally, in Study 5, we investigate the role of heuristic and non-heuristic decision-making in detecting deception and support our findings by mouse-tracking evidence. By investigating the differential role of the content under judgement, the processes to make veracity judgements, and the cognitive interplay between judges and deceivers, the studies presented in this thesis shed light into the cognitive mechanisms underlying the detection of deceitful opinions. Overall, this work supports a multi-dimensional view for the investigation, and possibly the improvement, of veracity judgements in security contexts.