The results of a new study suggest that if a bond with a friend is threatened or lost, if we see a friend in distress, or we become excluded socially, these experiences can cause us to feel physical pain.
A research team from the International School for Advance Studies (SISSA) in Italy conducted a series of experiments on a group of participants, during which their brain activity was measured using functional magnetic resonance imaging (fMRI).
The investigators say the way they conducted this study is innovative, compared with previous research looking at the association between social and physical pain.
"Classic experiments used a stylised procedure in which social exclusion situations were simulated by cartoons. We suspected that this simplification was excessive and likely to lead to systematic biases in data collection, so we used real people in videos," explains study author Giorgia Silani.
One of the experiments involved a game in which subjects tossed a ball to each other, but one of the players was deliberately excluded by the others. Either a player was excluded or a friend was excluded to trigger a condition of social pain.
In another experiment, a participant or the friend of a participant received a mildly painful stimulus. Each participant was a witness to their friend's experience and this triggered the condition of physical pain.
The researchers found that both conditions activated the posterior insular cortex of the brain, which is the region linked to the sensory processing of physical pain. This region of the brain was activated whether a person experienced the social or physical pain conditions themselves, or witnessed a friend experiencing both conditions.
According to the investigators, the feeling of social pain guides our behaviour. They explain that a person's ultimate goal is to "prioritise escape, recovery and healing," which is why we feel social pain and are able to empathise when others experience it.
Commenting on the research, study author Giorgia Silani says:
"Our findings lend support to the theoretical model of empathy that explains involvement in other people's emotions by the fact that our representation is based on the representation of our own emotional experience in similar conditions."
The results of the study are published in the journal Social Cognitive and Affective Neuroscience.