Love and Empathy Can Cause Aggression in Humans

One of humanity's greatest defining characteristics is its empathy-the ability to understand and feel for others. Yet what if this empathy can lead to harsher feelings? Scientists have found that under certain circumstances, feelings of warmth, tenderness and sympathy can predict aggressive behaviors.

In order to better understand the role that empathy plays in aggression, the researchers conducted a two-part study that involved a survey and an experiment. The survey asked participants to report on someone close to them and explain how that person was threatened by a third-party. Then, the volunteers were asked to describe their emotions and reaction to the situation.

After the survey, the scientists took saliva samples from participants to measure neurohormone levels. Then, the volunteers heard a compassion-evoking story about a pair of people that they never met. They were told that a couple in another room who were to take a math test would be exposed to a painful but harmless stimulus to measure the effects of physical pain on performance. During the test, the real subject had a choice on how much of a painful stimulus they would provide to the third party who was competing with the person they had compassion toward.

"The results of both the survey and the experiment indicate that the feelings we have when other people are in need, what we broadly call empathic concern or compassion, can predict aggression on behalf of those in need," said Michael Poulin, one of the researchers, in a news release. "In situations where we care about someone very much, as humans, we were motivated to benefit them, but if there is someone else in the way, we may do things to harm that third party."

In the end, the researchers found that two neurohormones are among the mechanisms that cause the aggressive response. These are chemicals that act as both hormones in the blood stream and neurotransmitters in the brain.

"Both oxytocin and vasopressin seem to serve a function leading to increased 'approach behaviors,'" said Poulin. "People are motivated by social approach or getting closer to others."

The findings are published in the journal Personality and Social Psychology Bulletin.