1-2% of the population are born with a rare condition that means that whenever they see someone else being touched, they feel a tactile sensation on their own body. These people report literally sharing the sensations of others, be it pleasure or pain. A new study shows that people with mirror touch synaesthesia (MTS) are so tuned into other people’s emotions, that they may even lose the ability to differentiate themselves from others. 

The findings were presented at an event as part of the ESRC's Festival of Social Science, the UK's largest annual celebration of social science. 

Professor Jennifer Rubin, ESRC Executive Chair, said: "The Festival of Social Science is one of the largest coordinated endeavours undertaken by a science community and demonstrates ESRC's commitment to public engagement. We know social scientists and economists value the opportunity to talk with the public to make an impact with their work. These events should inspire young people to pursue a career in social sciences and raise awareness about the impact made to wider society."

"Synaesthesia occurs when normally distinct senses get blurred together", says Michael Banissy, a Professor of Psychology at Goldsmiths, University of London. "For example some people can 'hear' colours, 'see' sounds, or even 'taste' words. In the case of mirror-touch synaesthesia, sight and touch overlap to the extent that if a synaesthete sees someone being touched on the face, they feel it on their own face."

Banissy has spent over a decade researching the causes of this phenomenon and is working on an ESRC project around understanding variations in level of empathy. In this latest study, he and his team decided to find out what effect MTS has on how people experience empathy.

The researchers developed a reliable test for MTS, which can grade people on a scale of 0-14, with seven or above indicating mirror-touch synaesthesia.

Then the scientists gave 100 people with a variety of scores on the scale an empathy questionnaire. The participants were asked to what extent they agreed with statements like 'I can tune into how someone else feels rapidly and intuitively', or 'I tend to get emotionally involved with a friend’s problems'. People with mirror-touch synaesthesia scored much more highly than controls on the emotional aspect of empathy, but not the cognitive aspect.

"Empathy has at least two aspects," says Professor Michael Banissy. "It consists of an emotional connection to someone else, so if someone is upset you are upset too. It also has a cognitive aspect, which is the ability to take someone else’s perspective and be able to put yourself in their shoes. In our study we found that people with mirror touch report a tendency to more readily share the emotions of others. However, they are not necessarily better at understanding other people because of this."

"What our study points to is that mirror touch synaesthetes don't just share the tactile senses of people, there is more to it than that," says Banissy. "These people appear to be more sensitive at picking up on subtle emotional cues, to the extent that when they see someone who is upset, they report a greater likelihood of feeling upset."

The findings shine a light on the science of how empathy works. Research shows that when we see faces depicting expressions such as happiness, anger or disgust, the same regions of our brain that are responsible for those emotions are activated.  Brain scans show that these brain networks involved in sharing the states of others are overactive in mirror-touch synaesthetes. However this 'overactivation' doesn’t tell the whole story. People with MTS may find it difficult to differentiate other people’s experiences and bodies from that of their own. 

"Our study shows that people with mirror touch have difficulty separating their version of their self from other people," says Dr Natalie Bowling, a researcher working with Professor Banissy. "We all have a psychological representation of what’s going on in our own body, and representations of other people. That’s how we understand other people’s emotions. However people with mirror touch find it difficult to separate out these two representations."