© Karl Tate, LiveScience Infographic ArtistWhen was the last time you told a lie?
Lying - like it or not - is a part of everyday life. Most of us will bend the truth every now and then, with even the most honest person telling the occasional "white lie" to avoid hurting someone else's feelings.
Yet some people, called
pathological liars, utter untruths constantly and for no clear reason. Their behavior confounds scientists and oftentimes themselves.
"Pathological liars have a pattern of frequent, repeated and excessive lies or lying behavior for which there is no apparent benefit or gain for the liar," said Charles Dike, clinical professor of psychiatry at Yale University and medical director of the Whiting Forensic Division of Connecticut Valley Hospital.
On the opposite end of the spectrum are those rare individuals who might be described as "pathological truth-tellers." These people forego socially convenient and appropriate fibs to speak the unvarnished, upsetting truth.
Intriguingly, this "lying handicap" is a common feature of the developmental disorder
high-functioning autism and Asperger's Syndrome.
"People with Asperger's have a tendency to be very blunt and direct - they can be honest to a fault," said Tony Attwood, professor of psychology at Minds & Hearts, an Asperger's and autism clinic in Brisbane, Australia
Psychology and neuroscience have provided clues as to why some people lie up a storm while others have difficulty dissembling or detecting it in others. These contrasting extremes can help us learn about the default human mode of lying on a daily basis to avoid insult, get out of trouble or exploit others.
"If you define lying as 'statements intended to deceive,' then yes we all do lie, every day," said Dike.