Conformity gets a bad rap, and it often deserves one. People abuse drugs, deface national parks, and spend $150,000 on tote bags after seeing others do so. Peer pressure doesn’t have to be all bad, though. People parrot each other’s voting, healthy eating, and environmental conservation efforts, too. They also “catch” cooperation and generosity from others. Tell someone that his neighbors donated to a charity, and that person will boost his own giving, even a year later. Such good conformity appears promising, but also narrow. Prior experiments, for instance, focus almost exclusively on people who observe others engage in a particular positive action (say, recycling) and later imitate that same action.

In a set of new studies, my colleagues and I highlight a broader flavor of positive conformity. We find that people imitate not only the particulars of positive actions, but also the spirit underlying them. This implies is that kindness itself is contagious, and that that it can cascade across people, taking on new forms along the way. To be a potent social force, positive conformity requires such flexibility. Not everyone can afford to donate to charity or spend weeks on a service trip to Haiti. Witnessing largesse in others, then, could inhibit would-be do-gooders who feel that they can’t measure up. Our work suggests that an individual’s kindness can nonetheless trigger people to spread positivity in other ways.

In our study, people were given a $1 “bonus” in addition to their payment for completing the study. They then viewed brief descriptions of 100 charities, and decided whether they wanted to give any of their bonus to each one. After making each donation, participants saw what they believed was the average donation made by the last 100 people in the study. In fact, we manipulated these “group donations” to influence our participants’ beliefs. Some people learned that they lived in a generous world, where people donated about three fourths of their bonus to charity. Others learned that they lived in a stingy world, where people donated only about one fourth of their bonus.

Like other scientists, we found that participants who believed others were generous became more generous themselves. We then tested our real question: does kindness contagion transcend mere imitation? In a follow up study, people observed others donating generously or stingily, and then completed what they thought was an unrelated “pen pal” task. They read a note in which another person described the ups and downs of his last month, and wrote back. People who had watched others donate generously wrote friendlier, more empathic, and more supportive notes than those who had watched others behave greedily. This suggests that kindness evolves as it diffuses, “infecting” behaviors through which new individual can express it.

People in our studies didn’t even need to see others do anything in order to catch their kindness. In another follow-up, people read stories about the suffering of homeless individuals. After each story, they saw what they believed was the average level of empathy past participants had felt in response to its protagonist. Some people learned that their peers cared a great deal, and others learned they were pretty callous. At the end of the study, we gave participants a $1 bonus, and the opportunity to donate as much of it as they liked to a local homeless shelter. People who believed others had felt empathy for the homeless cared more themselves, and also donated twice as much as people who believed others had felt little empathy.

We still don’t fully understand the psychological forces that power kindness contagion. One possibility, supported by our own work, is that people value being on the same page with others. For instance, we’ve found that when individuals learn that their own opinions match those of a group, they engage brain regions associated with the experience of reward, and that this brain activity tracks their later efforts to line up with a group. As such, when people learn that others act kindly, they might come to value kindness more themselves.

Of course, conformity is not always a force for good. Indeed, the ill will now blanketing our country often reflects people following each other’s lead. People who hold extreme attitudes voice them loudly; when moderate individuals fall in line, groups grow more entrenched and further apart from each other. The expanding, embittering gulf between left and right in American politics highlights the volatile results of such polarization. Our work, however, suggests that conformity can drive not just animosity, but also compromise, tolerance, and warmth.

The battle between dark and light conformity likely depends on which cultural norms people witness most often. Someone who is surrounded by grandstanding and antagonism will tend towards hostile and exclusionary attitudes herself. Someone who instead learns that her peers prize empathy will put more work to empathize herself, even with people who are different from her. By emphasizing empathy-positive norms, we may be able to leverage the power of social influence to combat apathy and conflict in new ways. And right now, when it comes to mending ideological divides and cultivating kindness, we need every strategy we can find.