Answer fast, or new lie detector will catch you out

The truth will out. A new lie detector test shows that it takes on average 30% longer to tell a fib than to be honest.

The discovery, following computer-based trials in Britain, will offer hope to law enforcement agencies struggling to keep pace with suspects who are getting better at lying.

The new device may also provide a more reliable alternative to conventional polygraphs, which critics believe implicate too many innocent people.



Aiden Gregg, a psychologist at Southampton University who developed the timed antagonistic response alethiometer (Tara), found that in 85% of cases interviewees were slower at faking answers than when telling the truth. Gregg believes that lying takes longer because it involves more complex cognitive activity.

The Tara test involves answering a series of questions displayed on a computer screen as quickly as possible by tapping responses on a keyboard. The programme records how long it takes each individual to answer and uses an algorithm to analyse the results.

Gregg said he built the test because he suspected that criminals were finding increasing ways to hide their dishonesty. “Habitual liars heard that people look away when telling lies, so they stare directly into your eyes,” he said. “However, we are not getting any smarter at detecting lies, and that could have serious consequences.”