Cognitive Load

The Imposing-Cognitive-Load Approach

Cognitive load can be defined as a multidimensional construct representing the effort that performing a particular task imposes on the actor's cognitive system. Lying can be more cognitively demanding than truth-telling, particularly during interviews. Formulating the lie, monitoring and controlling behavior, monitoring whether the interviewer appears to believe the lie, role-playing, justifying the lie, and suppressing the truth all add to cognitive load.

An investigator could exploit the different levels of cognitive load that truth-tellers and liars experience in order to more effectively discriminate between them. Liars who require more cognitive resources than truth-tellers will have fewer said resources left over. If cognitive demand is further raised, which could be achieved by making additional requests, liars may not be as good as truth-tellers in coping with these additional requests.

One way to impose cognitive load is by asking interviewees to tell their stories in reverse order. This increases cognitive load because it runs counter to the natural forward-order coding of sequentially occurring events, and it disrupts reconstructing events from a schema. Another way to increase cognitive load is by instructing interviewees to maintain eye contact with the interviewer. When people have to concentrate on telling their stories—which is likely when they are asked to recall what has happened—they are inclined to look away from their conversation partner (typically to a motionless point), because maintaining eye contact is distracting.

In two experiments, half of the liars and truth-tellers were requested to recall their stories in reverse order (Experiment 1) or to maintain eye contact with the interviewer (Experiment 2), whereas no instruction was given to the other half of the participants. More cues to deceit emerged in the reverse-order and maintaining-eye-contact [Page 159]conditions than in the control conditions. Moreover, observers who watched these videotaped interviews could distinguish between truths and lies better in the reverse-order and maintaining-eye-contact conditions than in the control conditions. For example, in the reverse-order experiment, 42 percent of the lies were correctly classified in the control condition, well below the amount typically found in verbal and nonverbal lie-detection research, suggesting that the lie-detection task was difficult. Yet, in the experimental condition, 60 percent of the lies were correctly classified, more than is typically found in this type of lie-detection research.

U.S. Army Pfc. Samantha Desvoignes, left, a human intelligence collector, conducts interrogation training with Sgt. Jeneane Eurell, role-playing as a prisoner during an exercise at Fort Hood, Texas, June 4, 2013. The cognitive-load perspective of lie detection consists of two approaches: the imposing-cognitive-load approach, which aims to make the interview setting more difficult for interviewees, and the strategic-questioning approach, which examines different ways of questioning that elicit the most differential responses between truth-tellers and liars. Lying can be more mentally demanding than truth-telling, particularly during interviews.

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