By Dr. Ken Broda-Bahm:
When it comes to assessing someone's believability and deciding whether they're lying to you or not, which works best: your quick "gut" intuition or more sustained and careful thought about it? It turns out, the answer is "neither." Immediate choices, as well as decisions made after longer deliberation, are both less reliable than judgments rendered after turning our minds away to focus on another task. This finding of a recent study (Reinhard, Greifeneder, & Scharmach 2013) suggests that unconscious processing is a better guide when assessing truthfulness. This advantage for unconscious processing might relate to some of the reasons I have always been a skeptic on human lie detecting ability. Short of Pinocchio's nose, there are very few reliable physical tells, and very few techniques that work in improving a receiver's ability to detect deception. Of course, there are potential exceptions, like the Lie to Me inspiration, Paul Ekman, but recent research suggests that human nonverbal response is far less universal and interpretable than previously believed.
Generally, the research supports a healthy skepticism. "Humans have been shown to be generally poor deception detectors," the Reinhard et al., authors write, noting that individuals tend to achieve an accuracy rate that is only slightly above the rate of a coin flip. The unreliability of these physical cues, in addition to the prevalence of false beliefs about what does or doesn't reveal a liar, essentially means that the less we rely on our own conscious thoughts about truthfulness, the better we do in assessing actual truthfulness. "Judges who were kept from consciously deliberating outperformed judges who were encouraged to do so or who made a decision immediately." This finding has implications in many legal contexts including attorney credibility or jury selection. For this post, however, I want to take a look at how this research, particularly within the broader frame of credibility and not just lie detection, should influence the way we assess witnesses.