Later On

A blog written for those whose interests more or less match mine.

Can you tell when someone’s lying? No.

leave a comment »

No better than chance. This article by Bruce Bower in Science News explains:

… A person’s perceived credibility, as reported by volunteers on questionnaires, rather than honesty, plays a major role in whether that person gets branded as a liar, Bond and DePaulo report in the July Psychological Bulletin. Certain people appear either honest or dishonest from the get-go, whether or not they’re telling the truth, the psychologists assert. Earlier research has found that baby-faced people seem credible whereas people who look nervous or avert their gaze typically get labeled 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 judgments depend more on the liar than the judge,” Bond says.

The new investigation challenges a view, championed by psychologists Maureen O’Sullivan of the University of San Francisco and Paul Ekman of the University of California, San Francisco, that a small number of individuals with considerable experience in unraveling certain kinds of lies do so with great accuracy. O’Sullivan and Ekman have found that a minority of psychotherapists quickly discerns lies about what a person says he or she is feeling, whereas insightful police officers readily discern a suspect’s crime-related deceits.

“There are significant differences among individuals in lie detection accuracy if you pick your subjects appropriately,” O’Sullivan says.

Bond and DePaulo disagree. They 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 judgments.

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 judgments 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. …

Complete article at the link.

Written by Leisureguy

5 July 2008 at 10:47 am

Posted in Daily life, Science

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: