Why would that be? One explanation is novelty. Perhaps the novelty of false stories attracts human attention and encourages sharing, conveying status on sharers who seem more “in the know.”

Our analysis seemed to bear out this hypothesis. Using accepted computerized methods for inferring emotional content from word use, we found that false stories inspired replies on Twitter expressing greater surprise than did true stories. The truth, on the other hand, inspired more joy and trust. Such emotions may shed light on what inspires people to share false stories.

As we learn more about how and why false news spreads, we should test interventions to dampen its diffusion. For example, though it was disheartening to learn that humans are more responsible for the spread of false stories than previously thought, this finding also implies that behavioral interventions may succeed in stemming the tide of falsity. It could be, for example, that labeling news stories, in much the same way we label food, could change the way people consume and share it.

Financial incentives are another possible tool. The social media advertising market creates incentives for the spread of false stories because their wider diffusion makes them profitable. If platforms were to demote accounts or posts that disseminated false stories, using algorithms to weed out falsehoods, the financial incentives would presumably be reduced. The tricky question, of course, would be: Who gets to decide what is true and false?

Our research is just the beginning. A more robust identification of the factors that drive the spread of true and false news will require direct interaction with users through interviews, surveys and lab experiments. We could also benefit from randomized controlled trials of efforts to dampen the spread of false stories.

Some notion of truth is central to the proper functioning of nearly every realm of human endeavor. If we allow the world to be consumed by falsity, we are inviting catastrophe.