Detecting Lies: Not as easy as we think

High tech machines, specially trained interrogators, liars exhibiting odd behavior – we’ve all heard of these things. New research, however, may suggest that these techniques are not as accurate as we once thought. In fact, many neurologists are going to lengths to say that even those with special training detect others’ lies no better than would be expected by chance.

Psychologists suggest that much of detecting deception is determined by the person who is deceiving. Many people are very easy to read while others are able to hide their intentions incredibly well.

Perceived credibility, reported by questionnaires and volunteers, as opposed to honesty, plays a vital role in determining whether someone should be deemed a liar.

In the July edition of Psychological Bulletin, Charles Bond Jr. of Texas Christian University in Fort Worth and Bella DePaulo of the University of California, Santa Barbara, explain in depth their findings based on the aforementioned information.

According to Bond and DePaulo, certain people are either honest or dishonest from the get-go. Earlier research found that baby-faced people seem credible whereas people who look nervous or avert their gaze are typically deemed untrustworthy. The new analysis shows that participants more often believe liars perceived as high in credibility than truth-tellers regarded as low in credibility.

“When all the evidence is statistically analyzed, deception judgements depend more on the liar than the judge,” Bond says. (Source).

This current research conflicts with previous research that suggests that most psychotherapists quickly discern lies about what a person says he or she is feeling, whereas insightful police officers readily discern a suspect’s crime-related deceits.

Maureen O’Sullivan of the University of San Francisco says, “There are significant differences among individuals in lie detection accuracy if you pick your subjects appropriately.” However, Bond and DePaulo respectively disagree. According to ScienceNews.org, Bond and DePaulo devised a new statistical method for estimating the range in the percentage of lies and truths that groups of volunteers would accurately identify if a lie-detection test was infinitely long. The technique corrects for measurement errors that occur on standard lie-detection tests, especially those requiring only a few true-or-false judgements.

The researchers applied this statistical tool to data from 142 earlier laboratory studies of lie detection. In these investigations, 19,801 judges assessed the veracity of 2,945 people conveying either true or false information. Many studies involved only college students as either judges or potential liars, but a substantial minority consisted of people with real-world lie-detection experience who were making deception judgements relevant to their professions.

Overall, participants accurately detected lies an average of 54 percent of the time, when an overall average of 50 percent would be expected by chance. This figure aligns with what researchers already knew.

But Bond and DePaulo focused on an individual’s performance, not a group average. They found that the highest detection rate achieved by an individual in these studies, which peaked at about 75 percent, did not exceed the maximum rate that guessing would have yielded, the researchers say. Individual differences in lie-detection accuracy were small, with scores clustering near the overall average of 54 percent correct.

Experienced judges displayed no lie-detection advantage over inexperienced ones. Neither did judges show greater accuracy in evaluating highly motivated liars, such as crime suspects, compared with less-motivated liars, such as college students pretending to have stolen money.

The researchers also found that the tendency to label someone as a liar also depended on whether a judge regarded other people as generally truthful or not.

Bond and DePaulo call for experiments that examine the complexity of real-world lie detection. Outside the laboratory, people infer deception from many lines of information, not just a person’s immediate behavior and speech, they say. In these situations, lies get identified over days, weeks or longer, rather than at the time a lie is told.

O’Sullivan also sees a need for research that addresses such issues. But she maintains that some people, due to their professional experiences, can quickly detect certain types of lies. In a new study submitted for publication, she and her colleagues find that experienced police officers rapidly identify high-stakes lies told by actual crime suspects far more often than they identify low-stakes lies told by students.

Tags: Brain, Deceit, Liars, Neurology, Psychology