While previous research shows outrage and division drive engagement on social media, a new study of digital behaviour during the 2024 US election finds that this effect flips during a major crisis – when "ingroup solidarity" becomes the engine of online virality.
Psychologists say the findings show positive emotions such as unity can cut through the hostility on social media, but it takes a shock to the system that threatens a community.
In a little over a week during the summer of 2024, the attempted assassination of Donald Trump at a rally (July 13) and Joe Biden's suspension of his re-election campaign (21 July) completely reshaped the presidential race.
The University of Cambridge's Social Decision-Making Lab collected over 62,000 public posts from the Facebook accounts of hundreds of US politicians, commentators and media outlets before and after these events to see how they affected online behaviour.*
"We wanted to understand the kinds of content that went viral among Republicans and Democrats during this period of high tension for both groups," said Malia Marks, PhD candidate in Cambridge's Department of Psychology and lead author of the study, published in the journal Proceedings of the National Academy of Sciences.
"Negative emotions such as anger and outrage along with hostility towards opposing political groups are usually rocket fuel for social media engagement. You might expect this to go into hyperdrive during times of crisis and external threat."
"However, we found the opposite. It appears that political crises evoke not so much outgroup hate but rather ingroup love," said Marks.
Just after the Trump assassination attempt, Republican-aligned posts signalling unity and shared identity received 53% more engagement than those that did not – an increase of 17 percentage points compared to just before the shooting.
These included posts such as evangelist Franklin Graham thanking God that Donald Trump is alive, and Fox News commentator Laura Ingraham posting: "Bleeding and unbowed, Trump faces relentless attacks yet stands strong for America. This is why his followers remain passionately loyal."
At the same time, engagement levels for Republican posts attacking the Democrats saw a decrease of 23 percentage points from just a few days earlier.
After Biden suspended his re-election campaign, Democrat-aligned posts expressing solidarity received 91% more engagement than those that did not – a major increase of 71 percentage points over the period shortly before his withdrawal.
Posts included former US Secretary of Labor Robert Reich calling Biden "one of our most pro-worker presidents", and former House Speaker Nancy Pelosi posting that Biden's "legacy of vision, values and leadership make him one of the most consequential Presidents in American history."
Biden's withdrawal saw the continuation of a gradual increase in engagement for Democrat posts criticising Republicans – although over the 25 July days covered by the analysis, almost a quarter of all conservative posts displayed "outgroup hostility" compared to just 5% of liberal posts.
Research led by the same Cambridge Lab, published in 2021, showed how social media posts criticizing or mocking those on the rival side of an ideological divide typically receive twice as many shares as posts that champion one's own side.
"Social media platforms such as Twitter and Facebook are increasingly seen as creating toxic information environments that intensify social and political divisions, and there is plenty of research now to support this," said Yara Kyrychenko, study co-author and PhD candidate in Cambridge's Social Decision-Making Lab.
"Yet we see that social media can produce a rally-round-the-flag effect at moments of crisis, when the emotional and psychological preference for one's own group takes over as the dominant driver of online behaviour."
Last year, the Cambridge team (led by Kyrychenko) published a study of 1.6 million Ukrainian social media posts in the months before and after Russia's full-scale invasion in February of 2022.
Following the invasion they found a similar spike for "ingroup solidarity" posts, which got 92% more engagement on Facebook and 68% more on Twitter, while posts hostile to Russia received little extra engagement.
Researchers argue that the findings from the latest study are even more surprising, given the gravity of the threat to Ukraine and the nature of its population.
"We didn't know whether moments of political rather than existential crisis would trigger solidarity in a country as deeply polarised as the United States. But even here, group unity surged when leadership was threatened," said Dr Jon Roozenbeek, Lecturer in Psychology at Cambridge University and senior author of the study.
"In times of crisis, ingroup love may matter more to us than outgroup hate on social media."
