Empathy originates in our brain; it’s something that is defined by our brain structure, and is unique for everyone. Researchers at the University of Vienna have published a new study that examines how we empathize for others in pain — and found that it relies on our own experiences of pain.

The study, led by psychologist Claus Lamm and his team of scientists from all over the world, examined 100 participants to further understand how empathy works on a neurobiological level. They used a method known as the placebo analgesia effect — a robust and tried-and-true way to study brain activity. Analgesia is the inability to feel pain; they found that when they induced pain analgesia in the participants, those same people saw a reduction in empathy for others in pain.

“Here, we show that inducing pain analgesia also reduces pain empathy, and that this is associated with decreased activation of empathy-related brain areas,” the authors write. “We then document that blocking placebo analgesia via an opioid antagonist also blocks placebo analgesia effects on pain empathy.” In other words, when people’s own pain experiences were reduced, their empathy for others in pain was also lowered.

Participants in the placebo group showed less brain activity in the anterior insula and midcingulate cortex, brain regions that are “well-known major hubs in the neuronal empathy network,” Lamm said in the press release. “In addition, they are central parts of the endogenous opioid system, which is involved in pain regulation.”

Next, the researchers tested the brain’s opioid system — the brain’s natural way to reduce pain; it also controls reward and addiction in the brain. The opioid system is comprised of three opioid receptors (mu, delta, and kappa) which are activated by peptides like enkephalins, dynorphins, and endorphin. Morphine, one of the most common and effective painkillers in hospitals, activates the brain’s opioid system by activating these opioid receptors.

By blocking the opioid receptors in the brain, they induced a blockade on the placebo-empathy effect in 50 of the participants. In short, by stopping painkillers and heightening participants’ sense of pain, they were also able to control their empathy for others and make it stronger. “This result strongly suggests an involvement of the opioid system in placebo-empathy, which is an important step to a more mechanistic understanding of empathy,” Lamm said in the press release. “We are now wondering whether the observed effects in the opioid system act directly on empathic processes or whether these are only carry-over effects of the manipulation of self-experienced pain.”

While there are still many questions left unanswered, the research certainly brings up several fascinating points about empathy — and its foundation in our own personal experiences. Our ability to empathize and the extent of our personal empathizing may be grounded in our own perspectives.

“The present results show that empathy is strongly and directly grounded in our own experiences — even in their bodily and neural underpinnings,” Lamm explains. “This might be one reason why feelings of others can affect us so immediately — as we literally feel these feelings as if we were to experience them ourselves, at least partially. On the other hand, these findings also explain why empathy can go wrong — as we judge the feelings of others based on our own perspective.”

Source: Rutgen M, Seidel E, Silani G, Riecansky I, Hummer A, Windischberger C. Placebo analgesia and its opioidergic regulation suggest that empathy for pain is grounded in self pain. Proceedings of the National Academy of Sciences of the United States of Americai, 2015.