An unequivocally positive side-effect of all the "fake news" headlines has been a growing interest among social scientists to research the impact of fact-checking.
In one of the most recent studies (here in English), economists at the Paris School of Economics and Sciences Po found that providing factual information on immigration improved French voters' understanding but didn't reduce their likelihood to vote for the fact-checked politician.
This finding is in line with a study published earlier this year conducted on American voters.
The researchers surveyed 2,480 French individuals online in four regions where the far-right Front National party (FN) had done best in last year's regional elections. The sample was otherwise representative of the French population in terms of age, gender and population.
Respondents were put into one of four groups. The first group received false claims on immigration made by Marine Le Pen, the FN's presidential candidate. The second group obtained statistics on the same issues. The other two groups were given both or neither, respectively.
Across all groups, the researchers tested respondents' understanding of the facts, their support for Le Pen on immigration and their voting intentions.
The variation of factual understanding among these four treatments is immediately clear. In one of the three claims tested, Le Pen used photos from the migration influx into Germany and Hungary to claim that 99 percent of refugees were men. UN stats indicate that the actual share of adult males among migrants coming into Europe from the Mediterranean was 58 percent.
In the graph below, respondents are divided into deciles, and the correct answer marked with a red vertical line. The "informed" group correctly determined the share of men more than 60 percent of the time. Individuals given no information or the false claims by Le Pen were far more likely to suggest a higher percentage.
Overall, knowledge of the facts was negatively affected when respondents only read Le Pen's claims but improved when they were offered the facts alone or both the facts and Le Pen's claims.
"We don't get any backfiring on the facts," said Emeric Henry, one of the authors of the paper (also in line with recent findings). Le Pen supporters "update their facts, even if a bit less than the others."
More surprisingly, the intention to vote for Le Pen improved not just among respondents subjected to her claims but also among respondents who were offered the facts alone. The study calls this a "backfiring" effect too, though it relates to voting intentions rather than factual understanding.
"Attracting attention to migration increases the support for Le Pen even after controlling for the change of opinions," said Henry. He thinks this is in part due to the topic of immigration, a central plank of the FN's program.
The researchers wanted to share their results ahead of the election but are aiming to submit the study for publication — and to study the phenomenon further.
"The natural next step is to replicate on a very different issue," Henry said. "We targeted a topic and a candidate and we'd like to see if true for other candidates and other issues."