Seeing another person jam their fingers in the car door is enough to make even the toughest of us wince. But for some people, seeing another person hurt themselves causes more than just an “ooooo” or an “ahhhh”. It can trigger an actual real experience of pain: “mirror pain”.
But how is this possible? The important thing to remember here is that pain is just an experience. It is the end result of a long line of sensory, emotional, cognitive and motivational processes. So we don’t always need to get hurt to experience pain!
Although a painful thought at first, mirror pain may be quite common. In two independent studies, the experience of mirror pain was reported in 16% of amputees  and 30% of an undergraduate population .
‘Yeah, right’ you say? Well, we carried out several studies using neurophysiological techniques and found these reports are more than just anecdotal. In one study we used electroencephalogram (EEG) to look at the brains activity in response to pictures of pain. In amputees who experience mirror pain, we found a unique response in brain activity to images of pain which was not seen in controls .
We then wanted to test a hypothesis about what mechanistic factors may be driving mirror pain. One theory we developed is that mirror pain may result from a hyperactivity of ‘mirror systems’ involved in processing pain [4, 5]. Mirror systems for pain describe brain activity when we experience pain and when we see another person experience pain. In mirror pain, these mirror systems may be disinhibited and this may be why some individuals experience a conscious perception of pain.
One way to measure mirror system activity in humans is through transcranial magnetic stimulation (TMS), a method of brain stimulation. When applying TMS to the motor cortex we see a muscle twitch. When stimulating the motor cortex and presenting visual stimuli of an injury this muscle twitch gets smaller. This effect is also seen when we experience pain and so has been suggested to reflect mirror system activity for pain.
We found that by using TMS to the motor cortex and showing images of needles penetrating hands, amputees who experience mirror pain show a bigger muscle twitch to controls . We also found that when applying TMS to the motor cortex and showing no images, that amputees who experience mirror pain show no different brain response to controls . These results may support our hypothesis that mirror systems for pain are disinhibited for pain, but further research is needed.
All up, our research shows that mirror pain is more than just exaggerated responses to another’s pain. It may be too early to say why this happens, but as a first step, we can now say with some confidence that when some people say “ouch” to your pain, they really mean it.
About Dr Bernadette Fitzgibbon
Bernie finished her PhD in 2011 where she carried out the first investigations on mirror pain in people who have lost a limb(s). She is now based at Monash Alfred Psychiatry Research Center where she continues to investigate the perception of pain, and how this doesn’t always have to involve a physical origin.
If you are interested in helping us better understand why some people feel another’s pain and others do not, please feel free to complete our online questionnaire
 Fitzgibbon BM, Enticott PG, Rich AN, Giummarra MJ, Georgiou-Karistianis N, Tsao JW, Weeks SR, & Bradshaw JL (2010). High incidence of ‘synaesthesia for pain’ in amputees. Neuropsychologia, 48 (12), 3675-8 PMID: 20670636
 Osborn J, & Derbyshire SW (2010). Pain sensation evoked by observing injury in others. Pain, 148 (2), 268-74 PMID: 20005042
 Fitzgibbon, B.M., et al., Atypical electrophysiological activity in amputees who experience synaesthetic pain when observing pain in another. Social, Cognitive and Affective Neuroscience, in press.
 Fitzgibbon BM, Enticott PG, Rich AN, Giummarra MJ, Georgiou-Karistianis N, & Bradshaw JL (2012). Mirror-sensory synaesthesia: exploring ‘shared’ sensory experiences as synaesthesia. Neuroscience and biobehavioral reviews, 36 (1), 645-57 PMID: 21986634
 Fitzgibbon BM, Giummarra MJ, Georgiou-Karistianis N, Enticott PG, & Bradshaw JL (2010). Shared pain: from empathy to synaesthesia. Neuroscience and biobehavioral reviews, 34 (4), 500-12 PMID: 19857517
 Fitzgibbon BM, Enticott PG, Bradshaw JL, Giummarra MJ, Chou M, Georgiou-Karistianis N, & Fitzgerald PB (2012). Enhanced corticospinal response to observed pain in pain synesthetes. Cognitive, affective & behavioral neuroscience, 12 (2), 406-18 PMID: 22201037
 Fitzgibbon BM, Enticott PG, Bradshaw JL, Giummarra MJ, Georgiou-Karistianis N, Chou M, & Fitzgerald PB (2012). Motor cortical excitability and inhibition in acquired mirror pain. Neuroscience letters, 530 (2), 161-5 PMID: 23022471