Experts from the Psychology Department of the University studied 52 cases of people who had appeared on television in several countries talking to the public about safe return of their relatives or gathering information that could lead to the killers of their beloved persons.
According to authorities, half of these individuals based on data (DNA, etc.) appeared to lie and then were convicted of murder.
The American psychologists, for their part, found that the stress experienced by individuals every time they are telling lie does not allow them to control the contractions of the facial muscles.
In a video analyzed by the researchers appeared 26 liars and 26 people who told the truth. Specifically, the experts studied more than 20,000 frames of their performances on TV and found significant differences between them.
The experts focused especially on the facial muscle groups associated with sadness, joy and surprise such as: forehead muscles (frontalis), eyelid muscles and several groups of muscles of the mouth.
Based on the findings of the research, the muscles related to the expression of grief – the eyelid muscles and the levator muscle of angle of mouth – seemed to contract more frequently in people who were telling the truth.
In contrast, in the face of those who were lying there was a small contraction of the zygomatic major muscles, located around the mouth, and a full frontalis muscle contraction.
These movements, according to the experts, contributed to the failed attempt to look sad.
As the scientists emphasize, behind the lie there is an evolutionary component. On average we lie twice a day.