This collaborative project focused on two previously unexplored issues: (i) the discrimination between true and false intentions and (b) detecting deception among small cells of suspects. Both these issues are highly relevant given modern terrorism and current security threats. Uniquely the project was firmly embedded in psychological theory and considered deception to be strongly linked to attention, memory, processing capacities and behavioural control. The project examined how these aspects are linked to behavioural, verbal and physiological cues to deception.
The Belgian team investigated the role of response inhibition in lying and explored two of the predictions: (i) that the truth is initially activated during deceptive responses and (ii) that the dominant truth response has to be inhibited in order to lie. Hence, the effort associated with active response inhibition may reveal deception. After initial behavioural studies (2010-2011), the team went on to study event-related brain potentials (ERPs) and functional magnetic resonance imaging (fMRI). The findings supported the cognitive view on deception, with the brain doing overtime when lying. Importantly, the extra cognitive load associated with lying was not only observed with brain measures, but also with behavioural. This is a main contribution to the literature, as the validity of behavioural measures is debated. The studies showed that the validity of behavioural measures critically depends on its structural characteristics of the task in which it is measured. Specifically, provided that tasks force attention to the truth value, it seems that behavioural measures – most prominently response latencies – can be used to measure automatic activation of the truth response. Critically, this was found to be the case not only for past crimes, but also for criminal intentions.
By using highly realistic and novel experimental designs, the German team showed that memories of criminal events can be very robust and strengthened by emotional arousal. Such memory traces can be reliably decoded from the pattern of autonomic and brain activity, indicating that such techniques can be used to verify the presence of concealed crime related memories in suspects. Critically, this also holds true with respect to planned activities. In brief, it was shown that details of a planned crime could be identified from verbal, behavioural, and physiological responses. In addition, previously unknown information (e.g., the location of a hidden bomb) can be identified from the pattern of physiological activity in a group of suspects.
The Swedish team focused on the Strategic Use of Evidence (SUE) technique, an established technique for optimizing the value of the critical background information held by the interviewer during a suspect interview. For the first part (2010-11) the comparative efficacy of the SUE-technique was examined for suspects either lying or telling the truth about their intentions. The results showed that SUE-technique was highly effective in terms of eliciting cues for deception and truth-telling. For the latter part the SUE-technique was examined for small cells of suspects, and the technique proved to be successful also for these situations. The Swedish team also gained insights into the strategies used by suspects (both when lying about future events and for small groups).
