India, April 22 -- Experts have advised that if you suspect someone is a psychopath, you just have to look into their eyes. Researchers at Cardiff and Swansea universities investigated the effect of "nasty" images in a 2018 study, like mutilated bodies and threatening dogs, on participants who were psychopathic and even some who were not. What they found was shocking.

The researchers found that while looking at the pictures, the psychopaths' eyes did not experience pupil enlargement, which was described as an "unusual reaction." However, on the other hand, the pupils of non-psychopathic participants widened and dilated while looking at the shocking pictures, which is a natural response.

"Our findings provide physical evidence of an emot...