With Motivation And Training, Some Professionals Can Catch A Liar

UCSF psychologists have found that individuals with aspecial interest in deception are able to detect a liarbased on split second facial expressions, gestural slips,and subtle signs in speech. Their findings will bepublished in this month's issue of Psychological Science.

"The ability to accurately detect deceit is real," says PaulEkman, PhD, UCSF professor of psychiatry and principalinvestigator of the study. "The information is there andwe've shown that a few groups of people can utilize it,although most law enforcement officials and mostpsychologists miss it."

The 627 people who participated in the study includedsheriffs, judges, police, intelligence officials, andpsychologists. They were categorized into 7 groups based ontheir profession - either psychologists or law-enforcementagents -- and interest and experience level in deception.

The researchers measured how well each group could detectdeceit based upon demeanor. Participants watched videotapesof ten males, ages 18 to 28, who either lied or told thetruth about their deeply-held opinions on controversialsocial issues. The participants then had ten seconds todecide if the subjects had given true or false opinions.

A group of 23 federal law enforcement officers, whichincluded CIA agents, was the most accurate and decidedcorrectly 73 percent of the time, on average. This wassignificantly better than a group of 84 federal judges (62percent accuracy, on average) and a group of 36 municipal,state, and federal law enforcement personnel with no specialinterest in deception (51 percent accuracy, on average).

Clinical psychologists performed better than academicpsychologists, most likely because of their greaterexperience conducting interviews, said Ekman. A group of107 clinical psychologists highly interested in deceptionand a group of 209 clinical psychologists moderatelyinterested in deception had average accuracy rates of 68 and62 percent, respectively. A group of academic psychologistshad an average accuracy rate of 58 percent.

Previous studies by the UCSF researchers showed that U.S.Secret Service agents could determine when people were lyingabout their emotions. The current findings show for thefirst time that accurate judgments are not confined toselected law enforcement groups, such as the Secret Service,and that it is possible for motivated observers to detectthe kind of lies law enforcement and intelligence agentsroutinely encounter.

Although some of the groups tested better than others, asubstantial number of people in every category performed ator below chance. This suggests that even judgments made byprofessionals with training in deception will not always beaccurate, said Ekman.

"Judging deception from facial expressions and body languagewill probably never be sufficiently accurate to beadmissible in the courtroom," says Ekman. "Without theproper training and motivation, most people, even thoseentrusted by society to assess a person's trustworthiness,do quite poorly."

Perhaps the most surprising result uncovered by theresearchers was that the most accurate groups were better atdetecting lies than detecting truths. The federal officersgroup accurately detected lies 80 percent of the time butdetected truths only 66 percent of the time. The samepattern held true for both groups of clinical psychologists,and a group of 43 Los Angles County sheriffs.

In addition to Ekman, co-authors of the study includeMaureen O'Sullivan, PhD, professor of psychology at theUniversity of San Francisco, and Mark Frank, assistantprofessor of communication at Rutgers University.