We mis­tak­enly attribute fid­get­ing, stut­ter­ing and avoid­ance of eye con­tact as out­ward sig­nals of men­dac­ity, sug­gests recent research into lie detec­tion, show­ing that these are some of the least accu­rate ways to pre­dict whether or not some­one is lying.

Instead, the most reli­able way to tell if some­one is lying is by lis­ten­ing care­fully:

Pro­fes­sor Richard Wise­man […] says that com­mon sense is the lie-buster’s best weapon, and affirms that it is aural rather than visual clues that are key.

Wiseman’s 1994 exper­i­ment […] had 30,000 par­tic­i­pants watch­ing or lis­ten­ing to two inter­views he con­ducted with Robin Day. In one, Day told the truth; in the other he lied. View­ers could not spot the lie: there was a near-50/50 vote. Radio lis­ten­ers, how­ever, achieved over 70 per cent accuracy.

“Lying taxes the mind,” Wise­man explains. “It involves think­ing about what is plau­si­ble. Peo­ple tend to repeat phrases, give shorter answers, and hes­i­tate more. They will try to dis­tance them­selves from the lie, so use far more imper­sonal lan­guage. Liars often reduce the num­ber of times that they say words like ‘I’, ‘me’, and ‘mine’. To detect decep­tion, look for aural signs asso­ci­ated with hav­ing to think hard.”

Accord­ing to the Cana­dian Jour­nal of Police and Secu­rity Ser­vices, another side-effect of lying that foren­sic inter­roga­tors will look for is the avoid­ance of ver­bal con­trac­tions — using “I am” instead of “I’m” and so on.