Groups can catch lies better than individuals

Groups are consistently more accurate in distinguishing truths from lies than one individual, according to a new study.
Researchers from the University of Chicago Booth School of Business designed four experiments in which groups consistently distinguished truth from lies more accurately.
However, the group advantage in lie detection comes through the process of group discussion, and it is not the product of a "wisdom of crowds" effect, researchers said.
"We find a consistent group advantage for detecting small 'white' lies as well as intentional, high-stakes lies told for personal gain," said Chicago Booth Professor Nicholas Epley.
"This group advantage seems to come through the process of group discussion rather than statistical aggregation of individual opinions," Epley said.

The modest accuracy rate of people who can detect deception is driven mostly by the tendency to detect truths, rather than lies, researchers said.

This has led other researchers to develop costly training programmes that target individual lie detectors to increase accuracy. Epley and colleagues tested a different strategy: asking individuals to detect lies as a group.
In the first two experiments, subjects watched videos of different statements from different speakers and guessed whether each statement was a truth or a lie, either individually or in three-person groups.
The only difference between the two experiments was that in the second, researchers used different statements and also nearly doubled the sample size.

In both, results were replicated: Groups were more accurate than individuals (61.7 per cent and 60.3 per cent group accuracy in Experiments 1 and 2, respectively, compared to 53.55 per cent and 53.56 per cent individual accuracy).
The third experiment tested whether the group advantage in lie detection applied to high-stakes and intentional lies.
Groups were again more accurate, with 53.2 per cent over 48.7 per cent in individual accuracy.
The fourth experiment focused on two underlying reasons groups could better identify deception than individuals: first, group discussion could identify the most accurate person within a group which increases accuracy through a sorting mechanism; and secondly, group discussion could elicit observations about the target that provide information needed to make an accurate assessment.

"Interventions to improve lie detection typically focus on improving individual judgment, which is costly and generally ineffective," Epley said.
"Our findings suggest a cheap and simple synergistic approach of enabling group discussion before rendering a judgment," Epley added.