Instagram Pushed 74% Pro-Bolsonaro Content to Test Account Before Brazil Runoff

Instagram's recommender system delivered 74% pro-Bolsonaro and right-leaning content to a neutral test account in the days before Brazil's October 25 runoff, against 18% pro-Lula and left-leaning content, according to research published Friday by the nonprofit Ekō. The finding directly contradicts Meta's sworn statement to Brazil's Superior Electoral Court that it "has adopted measures to ensure equal treatment" of President Luiz Inácio Lula da Silva and challenger Flávio Bolsonaro.

The experiment ran from October 14. Researchers created a fresh Instagram account, followed both candidates and their parties, and viewed posts without engaging — a standard method for isolating algorithmic preference from user behavior. Of the 50 posts the algorithm served, the political content split 74% right versus 18% left, which Ekō called "glaring evidence of a significant right-wing bias in Instagram's recommender systems."

Does engagement explain the imbalance?

No. Ekō's numbers show the opposite pattern. Pro-Lula posts averaged 398,000 likes, roughly 64,000 comments, and 108,000 shares each. That is more than double the likes, over seven times the comments, and more than nine times the shares of the average pro-Bolsonaro post.

"Pro-Lula/left-leaning content performed better per post on every engagement measure, yet was recommended far less often, undercutting any claim that Instagram's algorithm is simply showing users content that is performing best," Ekō said. The researchers concluded the system was "aggressively promoting" Bolsonaro content while "actively suppressing Lula's official campaign account."

One recommended post showed military police officer Sargento Castro beside a smiling Bolsonaro. Its caption read: "If you try to fight back, you're going straight into a body bag."

What does this change for the campaign?

Plenty, if verified. Vanessa Lemos, a senior campaigner at Ekō, said Meta is "interfering in Brazil's elections in plain sight — boosting Bolsonaro and suppressing Lula content." Her demands are concrete: "Meta must prove it is complying with the electoral court's equal-treatment order, verify who pays for political ads, and make its moderation decisions appealable."

The stakes extend past one election. Lula has formally requested Bolsonaro's disqualification from the race over Meta's alleged interference. According to the reporting, Meta employees have acknowledged internally that Lula's accounts faced restrictions before the vote.

United Nations experts added their warning on Wednesday. "Monitoring reports show thousands of accounts and posts have faced suspensions, reduced visibility, and sharing limits, including journalists, human rights defenders, civil society actors, and content creators," they said. Their statement noted that information "including from Meta employees, suggests that accounts linked to one side of the presidential race were disproportionately curtailed."

US lawmakers also acted. In a letter to Meta CEO Mark Zuckerberg earlier this week, they demanded the company "take immediate action to ensure that, going forward, candidates and their campaigns in democratic elections receive equal treatment and access on your platform."

A caveat on the methodology

The Ekō study rests on a single new account and 50 posts — a probe, not a census of Instagram's recommender behavior. It has not been independently replicated, and Meta disputes its premise. The engagement differential, however, is the strongest signal in the data: recommendation volume moved against the direction of measured performance.

The result, despite the imbalance

Lula won Sunday's runoff anyway. With 99.99% of votes counted, he took 51.79% to Bolsonaro's 48.21%, becoming the first Brazilian candidate since democracy's 1985 restoration to win a second round after losing the first. "I would like to thank the Brazilian people for the generosity they have shown me for a long time," Lula said in his São Paulo victory speech, crediting Brazilian youth who "took to the streets to defend democracy."

Francesca Emanuele of the Center for Economic and Policy Research, monitoring from São Paulo, noted the win came "despite the unfair practices his campaign has faced from Meta" and election-day bus shortages in Salvador and São Paulo, where the Supreme Court extended voting by two hours.

Bolsonaro has refused to concede, calling the result "impossible to concede" over the polling-hours extension. With the Superior Electoral Court, UN experts and US Congress now all pressing Meta on equal treatment, the company's recommender systems face sustained scrutiny well past this runoff.