Introduction
Have you ever cried with a friend because she was sad and not necessarily because you were? After having heard her problems you not only feel sympathy for her, but it goes a bit further: You actually feel sad because she is sad? This is a capacity called empathy, which is useful in everyday life to understand fellow humans and to predict how people will behave. Empathy allows you to adopt the point of view of another person and experience the affective reactions of the other as well. It makes it easier for you to connect with other people, to interact with them and to form connections. Up till now, there is yet no agreement on how empathy works: Do we actually merge ourselves to others or do we recognize a distinction between ourselves and the other in need?

Two points of view
Evidence exists for both theories. In favour of the view that we merge ourselves with others is the finding that empathy is more easily evoked when the other is similar to ourselves. On the other hand there is also support for the theory that we distinguish ourselves from others: We can experience different empathic feelings, depending on the perspective we choose to take on a situation. Furthermore, different brain areas are active when we think about our own pain compared to pain of others. To find out which theory could be true, research on the neuromodulator oxytocin was carried out. Why oxytocin? Because this neuromodulator is known for its role in empathic behaviour. Oxytocin elicits feelings of trust, attachment and perspective taking and it thereby enhances empathy.

Research on oxytocin
In this research subjects were tested twice: They were once administered oxytocin and once a placebo. Both times they were asked to review pictures of human hands and feet, which were either in pain or not. They subsequently had to indicate how much this would hurt them or others. The influence of oxytocin was studied by comparing the imagined pain under oxytocin and placebo. Thereby, support for one of the two described mechanisms could be gained. If people do not distinguish themselves from others it should not matter which person is in pain, as both will experience the same pain. However, if people do distinguish themselves from others, the experienced pain will differ between these individuals.

Results: distinction me and you
When participants were administered with a placebo, they rated equal amounts of pain to themselves and others. However, when participants were administered with oxytocin, they rated more pain to others than themselves. Oxytocin thus increases empathy for the other and thereby enhances the recognition of differences between ourselves and the other. This experiment supports the theory that empathy is caused by distinguishing ourselves from others. Furthermore, it shows that oxytocin sharpens the boundaries between self and others and its modulatory role in empathy. This research brings us one step closer to discovering the mechanism underlying empathy.

References
Abu-Akel, A., Palgi, S., Klein, E., Decety, J., & Shamay, S. (2015). Oxytocin increases empathy to pain when adopting the other - but not the self-perspective. Social Neuroscience, 10, 7-15.