[1] In 2003, psychologist Bella DePaulo, now affiliated with the University of California, Santa Barbara, and her colleagues combed through the scientific literature, gathering 116 experiments that compared people’s behavior when lying and when telling the truth. The studies assessed 102 possible nonverbal cues, [2] None proved reliable indicators of a liar, though a few were weakly correlated, such as dilated pupils and a tiny increase — undetectable to the human ear — in the pitch of the voice.

Three years later, DePaulo and psychologist Charles Bond of Texas Christian University reviewed 206 studies involving 24,483 observers judging the veracity of 6,651 communications by 4,435 individuals. Neither law enforcement experts nor student volunteers were able to pick true from false statements better than 54 percent of the time — just slightly above chance. In individual experiments, accuracy ranged from 31 to 73 percent, with the smaller studies varying more widely. [3] “One of the problems we face as scholars of lying is that everybody thinks they know how lying works,” says Hartwig, who coauthored a study of nonverbal cues to lying in the Annual Review of Psychology. 

This size effect suggests that the greater accuracy reported in some of the experiments may just boil down to chance, says psychologist and applied data analyst Timothy Luke at the University of Gothenburg in Sweden. “If we haven’t found large effects by now,” he says, “it’s probably because they don’t exist.”

Common wisdom has it that you can spot a liar by how they sound or act. But when scientists looked at the evidence, [4] they found that very few cues actually had any significant relationship to lying or truth-telling. Even the few associations that were statistically significant were not strong enough to be reliable indicators.

Police experts, however, have frequently made a different argument: that the experiments weren’t realistic enough. After all, they say, [5] “The ‘guilty’ people had nothing at stake,” says Joseph Buckley, president of John E. Reid and Associates, which trains thousands of law enforcement officers each year in behavior-based lie detection. “It wasn’t real, consequential motivation.”

Samantha Mann, a psychologist at the University of Portsmouth, UK, thought that such police criticism had a point when she was drawn to deception research 20 years ago. [6] The interpersonal deception theory posits that interpersonal deception is a dynamic, iterative process of mutual influence between a sender, who manipulates information to depart from the truth, and a receiver, who attempts to establish the validity of the message.Then Mann asked 65 English police officers to view the six statements and judge which were true, and which false. Since the interviews were in Dutch, [7] the officers were given donuts as a reward for participating in the experiment.

[8]  1 In fact, the killer maintained eye contact and did not fidget while deceiving.    2“This guy was clearly very nervous, no doubt,” Mann says, but he controlled his behavior to strategically counter the stereotypes. 3 And the officers who did worst were those who said they relied on nonverbal stereotypes like “liars look away” or “liars fidget.” 4 The officers were correct 64 percent of the time — better than chance, but still not very accurate, she says.

In a later study, also by Mann and Vrij, 52 Dutch police officers did no better than chance at distinguishing true and false statements given by family members who’d murdered their relatives but denied it in anguished displays during televised press conferences used in the study. Notably, officers who performed the worst were those who felt that the emotional displays were genuine.[9]  “If a husband killed his wife, he could be upset for all kinds of reasons, [10] like remorse or getting caught,” says Mann. “Nonverbal behavior is so idiosyncratic. If you focus on the nonverbal behavior like emotions, you will trip up.”

Confirming these results on a large scale years later, Hartwig and Bond reviewed the literature for studies comparing people’s abilities to detect high- and low-stakes lies. [11]  Lastly, it has also been suggested that an unpleasant treatment used in a deception study or the unpleasant implications of the outcome of a deception study may be the underlying reason that a study using deception is perceived as unethical in nature, rather than the actual deception itself.

^{Magazine, S. (2022). Why Do Older Individuals Have Greater Control of Their Feelings?. Retrieved 7 July 2022, from https://www.smithsonianmag.com/science-nature/why-do-older-individuals-have-greater-control-their-feelings-180977693/}