The eyes may not be the window to the soul, according to a study which found we detect strong emotion in others by studying their body language and not their face.
Contrary to popular belief, looking at someone's face alone is not enough to tell us whether they are roaring in celebration or screaming in frustration, researchers claimed.
While people may believe they have the ability to read each other's faces, body language is the real clue that reveals whether strong emotions someone is feeling are feeling are positive or negative.
In a study published in the Science journal, groups of participants were shown a series of intense facial expressions – such as tennis players photographed just after winning or losing a point.
In some cases the volunteers were able to see the player's full body, but in others they were only shown either their face or their body with the other removed.
Participants could clearly tell whether the players were winning or losing when shown the full picture or just the body, but their guesses were no better than chance when based on the face alone.
Those who were allowed to see the full image were convinced they had made their judgment based on the players' facial expressions even though results from the two other groups suggested otherwise.
The researchers, from New York and Princeton Universities and the Hebrew University of Jerusalem, carried out a second study where volunteers were shown a wider range of faces depicting emotions including joy, pleasure, victory, grief, pain and defeat.
Using photo editing software, the researchers attached the faces to bodies expressing the opposite emotion, and asked participants to act out the emotions they saw in the photos.
The resulting poses mimicked the body poses in the photographs but not the facial expressions, demonstrating that people base their interpretation of strong emotions on cues in the body and not the face, the researchers reported.
Dr. Hillel Aviezer, who led the study, said: "These results show that when emotions become extremely intense, the difference between positive and negative facial expression blurs.
"The results may help researchers understand how body/face expressions interact during emotional situations. For example, individuals with autism may fail to recognise facial expressions, but perhaps if trained to process important body cues, their performance may significantly improve."