Stress is a major factor to find empathy, according to researchers at McGill University in Montreal. The study suggests that biochemical changes related to stress prevents emotional contagion in the animals.
The research suggested that a drug that blocks stress hormones increases the ability of college students and mice to feel the pain of a stranger and that phenomenon, known as 'emotional contagion of pain' is one form of empathy. Researcher Jeffrey Mogil said, "We found what in some sense might be thought of as the secret to empathy, that is, what prevents it from occurring more often between strangers and the secret is quite simply stress, and in particular the social stress of being in close proximity with a stranger."
Researchers treated male mice with a stress hormone-blocker called metyrapone and observed their response to the pain of other mice. They found that the drug allowed greater empathy as mice began reacting to strangers in a manner normally reserved for familiar cage-mates. In other tests, when the mice were put under stress, the mice showed less empathy when their peers were in pain.
The study appears in the Cell Press journal Current Biology.