First, she gathered up 282 online volunteers who hailed from various countries but were mostly young and female. They took a 41-question personality quiz designed to assess their levels of subclinical narcissism, checking boxes next to statements like “I like to have authority over other people” or “I will be a success.” They then read a story about a person named Chris who had just gone through a breakup, and then took another quiz to determine how bad they felt for Chris. The more narcissistic among them were indeed less likely to feel empathy for the fictional jilted man.

An important note here: The study participants, though they’re described as “narcissists,” were not clinically diagnosed with Narcissistic Personality Disorder, a bona-fide mental illness. Psychologists aren’t sure how much overlap there is between functional people who are very narcissistic and those who suffer from NPD. One rule of thumb, Hepper tells me, is that most ordinary narcissists are happy, while NPD tends to lead its sufferers to extreme dissatisfaction with life.

For her next manipulation, Hepper and her co-authors asked a group of 95 female undergrads to take the same narcissism quiz, and then later to watch a 10-minute documentary about Susan, a victim of spousal abuse. Half were told to try to put themselves in Susan’s shoes (“Imagine how Susan feels. Try to take her perspective in the video...”), while the others were told to imagine they were watching the program on TV one evening.

The subjects who were told to take Susan’s perspective were significantly more likely to score higher on empathy. In fact, the more narcissistic they were, the more the trick seemed to work.

“I think what's going on here is that people who are low on narcissism are already responding to people—telling them what to do isn't going to increase their empathy any further,” Hepper said. “But the higher on narcissism you get, the less empathy [you feel]. By instructing them to think about it, it activates this empathic response that was previously much weaker.”

And the narcissists weren’t just faking it. In a third experiment, Hepper showed that extreme narcissists had lower-than-average heart rates when listening to a recording of a woman in distress. (That is, “Their lack of empathy is more than skin-deep,” Hepper writes.) But if they were told to take the woman’s perspective, their heart rates leapt back up to a normal level.

Hepper thinks that eventually, this research could help shape therapeutic interventions aimed at narcissists. Teachers or human resources representatives could use such tools to try to get their resident egomaniacs to be more charitable.

Perhaps one day we can banish all the world’s narcissists to a desert island littered with tanning beds and TV cameras. Until that day, this type of compassion training might be the best weapon we have against the self-absorbed. As Hepper said, maybe it can help make the world “a nicer, more prosocial place.”