People who lie can now be caught by the unique brain activity visible in MRI scans, a study has shown.
The US team said that the study could help shed light into what goes on in the minds of people with mental disorders.
"The study is a way to probe the way that we think how other people think about us," the BBC quoted Read Montague of the Baylor College of Medicine in Houston, as saying.
For instance, you send a resume that presents a certain picture of you and then you walk into an interview and you say things in order to manipulate in the mind of the interviewer a model of you in their mind - this is called second-order belief or "the ability and willingness to manipulate other people's beliefs about ourselves for gain."
During the study, participants played a game where "buyers" had to pass on information about an object's value to the "sellers", in order to buy the object as cheaply as they could.
"Somebody sends a suggestion to you, saying 'You should sell me this thing for such and such amount of money', and the other person has to decide what that person means by those signals, what does that person think I think about them," explained Montague.
About 11percent of the players consciously tried to deceive their opponents by making them believe they were being honest - thus aiming to reap higher profits.
The researcher said that this study was an important step towards understanding mental disorders, including autism.
Montague explained that people with personality or mental disorders did not process social information appropriately. But asking a person with a mental illness to play a strategic computer game could help provide insights into a specific disorder.
The study is published in the journal PNAS.