Verbal and Nonverbal Behaviour as a Basis for Credibility Attribution

pinoccioThe Journal of Experimental Social Psychology has given subscribers a sneak preview of an article on lie detection from Marc-Andre Reinhard and Siegfried Sporer that has just been accepted for publication. The researchers were interested in the impact on credibility assessment when people were not highly motivated to detect deception, and/or were distracted with other tasks.

Reinhard and Sporer showed that when participants were not highly motivated or were distracted they tended to rely on non-verbal cues to decide whether someone’s story was credible. When participants were motivated and could concentrate on the task, they used both non-verbal and verbal cues to judge the plausibility and credibility of the story.

The theory that we process information superficially in conditions of low motivation or high cognitive load, and more carefully when we are motivated and have more cognitive capacity, is the basis of several so-called dual process models. We know from research on dual process models that when we have a lot of other things to think about, we’re rushed or we don’t really care about the task we tend to base our judgments on superficial cues. Under such circumstances we tend not to bother with thinking too hard about what we are doing. Advertisers and salespeople know very well that in low motivation conditions we won’t think too much about the ‘buy this’ message if it comes from someone who is good-looking / authoritative, and that when we see the words ‘last chance to buy’ we’ll use this as an automatic cue that the product is valuable. (Robert Cialdini has many other examples of how easily we are swayed in his classic text Influence.) But this is the first time that dual process theories have been applied to lie detection. As Reinhard and Sporer note:

our studies have shown that dual-process theories can help us to understand the process of lie detection. These theories also allow predictions about the conditions under which people are worse or better lie detectors.

The researchers did not check whether or not these participants were actually more accurate at detecting deception, they just explored what strategies were used to assess credibility. (I guess that’s a study for another day.) But we do know that there is no single “Pinocchio’s nose”-type cue for detecting lies. You stand a better chance of catching a liar if you use multiple sources of information and use them to test the alternative explanations for what you are hearing. The results of this study suggest that people who are distracted or have low motivation will tend to rely on the “Pinocchio” approach. So people who are trying to assess credibility (for instance, law enforcement officers interviewing suspects or eyewitnesses; or jurors assessing the quality of witness testimony) need to concentrate on the task at hand to give themselves the best chance of using all the relevant cues to deception.

And if you’re a kid trying to fib to your parents, wait until they are busy with other tasks before you tell them your lie.


Abstract under the fold.

Photo credit: Anne in Beziers, Creative Commons License

Three experiments were able to demonstrate the usefulness of dual-process models for the understanding of the process of credibility attribution. According to the assumptions of dualprocess models, only high task involvement and/or high cognitive capacity leads to intensive processing of verbal and nonverbal information when making credibility judgments. Under low task involvement and /or low cognitive capacity, people predominantly use nonverbal information for their credibility attribution. In Experiment 1, participants under low or high task involvement saw a film in which the nonverbal behaviour (fidgety vs. calm) and the verbal information (low versus high credibility) of a source were manipulated. As predicted, when task involvement was low, only the nonverbal behaviour influenced participants’ credibility attribution. Participants with high task involvement also used the verbal information. In Experiment 2 and 3, the cognitive capacity of the participants was manipulated. Participants with high cognitive capacity, in contrast to those of low cognitive capacity, used the verbal information for their credibility attribution. Copyright © 2007 Elsevier Inc

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