The body naturally reduces the pain experienced if the limb or body part affected is focused on visually.
Researchers found that people had a higher pain threshold if they looked at the arm or hand being treated.
Furthermore, if the body part was made to appear larger, by using a mirror, then the analgesic effect of simply looking was also increased. The bigger the hand or arm appeared the less extreme the pain.
The study shows that pain is both sensory and emotional in the way in which is it experienced and could lead the way for new treatments for pain.
Professor in Neuroscience at John Moores University, Francis McGlone, said: "What this shows us is the very plastic processing of the way pain is represented in the brain. Vision affects pain processing."
The study, published in the journal Psychological Science, measured how acute pain was felt after a heat probe was applied to the hands of 18 participants. The visual image of their hands was manipulated using a mirror that varied the size.