Illustration by Nishant Choksi

Out of nowhere, a huge fad sweeps the country. It dominates social media and leads to a blizzard of think pieces, which are followed almost immediately by a backlash, as critics warn of the fad’s baleful consequences. Eventually, people get bored and move on to something new. That could well be the story of Pokémon Go, the augmented-reality game that has everyone wandering the streets in search of Pikachus and Squirtles. It’s also the story of the A.L.S. Ice Bucket Challenge, in 2014, in which millions of people filmed themselves dumping buckets of ice-cold water over their heads, in order to fight Lou Gehrig’s disease. Facebook users posted more than seventeen million videos of dousing, and countless celebrities—Bill Gates, Justin Timberlake, Leonardo DiCaprio—got drenched for the cause. For a few weeks, a previously little-known and underfunded disease dominated the public imagination.

But the feel-good story made some people feel bad. The challenge was derided as “slacktivism”—a way for people to feel virtuous without doing much. Critics fretted that the exercise amplified people’s tendency to donate for emotional reasons, rather than after careful evaluation of where money can do the most good. Some argued that it would divert donations from diseases that afflict many more people than the six thousand who receive a diagnosis of A.L.S. every year. People even attacked ice-bucketeers for wasting water.

All these critiques had the same underlying theme: the faddishness of the challenge undermined its value. This makes intuitive sense, but is it true? Actually, no. Silly though the Ice Bucket Challenge may seem now, it had far-reaching effects. It raised a reported two hundred and twenty million dollars worldwide for A.L.S. organizations; in just eight weeks, the American A.L.S. Association received thirteen times as much in contributions as what it had in the whole of the preceding year. Public awareness rose: the challenge was the fifth most popular Google search for all of 2014. Brian Fredrick, the vice-president for communications and development at the A.L.S. Association, told me, “The challenge suddenly made a lot of people who probably didn’t even know who Lou Gehrig was aware of the disease. It really changed the face of A.L.S. forever.”

More concretely, the money raised has led to more research and more spending on patient care. The A.L.S. Association has tripled its annual funding for research. “The research environment is dramatically different from what it was,” Barbara Newhouse, the association’s C.E.O., told me. “We’re seeing research that’s really moving the needle not just on the causes of the disease but also on treatments and therapies.” Last summer, a team from Johns Hopkins published a paper in Science that was hailed as a breakthrough in A.L.S. research; the team members said that funding from the challenge had accelerated the pace of their work.

It’s true that the vast majority of the people who made A.L.S. donations during the challenge haven’t done so again. But contributions to the A.L.S. Association have stayed about twenty-five per cent higher than in the year before the challenge, and the average donor age dropped from above fifty to thirty-five. The campaign was an enormous success with millennials, a demographic most charities have had a hard time reaching. The young are the demographic least likely to make charitable donations, and millennials seem more resistant to traditional charity appeals than previous generations. The challenge circumvented those problems by leveraging the power of social media to spread the word, and by making it easy for people to donate via their cell phones.

If the success of the challenge had come at the expense of other charities, ambivalence might be justified. But there’s almost no evidence that this was the case. According to Giving U.S.A., individual donations in the U.S. rose almost six per cent in 2014, which doesn’t suggest any cannibalization effect. Indeed, it’s likely that the very nature of the challenge, which belongs to a category known to anthropologists as “extreme ritual,” made people more openhanded. Dimitris Xygalatas, an anthropologist at the University of Connecticut who has studied the effects of such rituals, ran a fascinating experiment with people who were undergoing kavadi—a Hindu ritual that commonly involves piercing the skin with sharp objects and then making a long procession while carrying heavy objects. Xygalatas found that people who did kavadi, and even people who just joined in the procession, donated more to charity than people in a control group. And those who gave the most painful descriptions of the experience donated the most. As a result, Xygalatas has suggested that the Ice Bucket Challenge, far from stealing from other charities, almost certainly increased the total size of the pie.

That, really, was the true accomplishment of the challenge: it took tools—the selfie, the hashtag, the like button—that have typically been used for private amusement or corporate profit and turned them to the public good. The campaign’s critics implied that, had people not been dumping freezing water over their heads, they would have been working to end malaria instead. But it’s far more likely that they would have been watching cat videos or, now, playing Pokémon Go. The problem isn’t that the Ice Bucket Challenge was a charity fad. It’s that it was a charity fad that no one has figured out how to duplicate. ♦