Is information or motivation to blame for partisan beliefs?
Partisanship, whether you support a particular person, group, or cause, has long been known as a key factor in misinformed beliefs—from COVID-19 to Brexit. But how does partisanship drive bias and misinformation? Is it because people of different parties consume different media? Or are we motivated to be biased?
“This is an age-old debate in social psychology … whether something is due to basic cognitive processes or motivational processes,” said Tyler Hubeny, a social psychologist at the University of Texas at Austin. In a new study published in Psychological Science, Hubeny and his colleagues put these two competing theories to the test.
The new study sought to test a common argument that partisan bias arises from differential knowledge. In this theory, researchers frame partisan bias as a byproduct of the information ecosystem, where people of different party allegiances are exposed to different news sources, leading to differing knowledge bases and conclusions. But the flip side—and a more daunting cause of misinformation—is that partisan bias exists because people’s desires influence how they determine whether information is true or false.
“The aim was to try and test that and rule it out and say, well, if we completely take away the differences in prior beliefs, do we still see evidence of partisan bias? And if we do, then it probably is due to that motivational explanation,” Hubeny said.
The new study focused on the United States, where Hubeny and his colleagues recruited over 600 American citizens through an online portal. Instead of using a person’s existing political partisanship, such as Democrat or Republican, the researchers randomly split the participants into Team Spain, Team Greece, or No Team.
“We basically gave them this phony personality test, kind of like the ones you would see on Buzzfeed,” Hubeny explained. The test asked a series of personality questions, which determined the group the participant belonged in. By randomly assigning participants to teams, the researchers were able to eliminate any differences in knowledge that might have existed.
After a participant was given their assigned group, researchers then asked them to judge whether a series of statements were true or false. Some of the statements were favorable to Spain (e.g., “Spain has produced more Nobel Prize winners than Greece”), while others were favorable to Greece. The researchers then analyzed the responses using a method called signal detection theory, which allowed them to measure the participants’ truth sensitivity (how well a participant can distinguish true and false information) and acceptance thresholds (how often they would reject information in general).
The researchers found that even with the random teams, there was a partisan effect in how people determined the truthfulness of the information. This effect was present not because of any differences in knowledge, but because their arbitrary party identity shifted their acceptance thresholds.
“People were more accepting of the information that was congenial toward their randomly assigned team, and less accepting when that information was uncongenial toward their randomly assigned team,” Hubeny said. Therefore, the study supports the theory that partisan bias can exist because of motivational processes, outside of differential knowledge.
These findings have implications for misinformation interventions. “Oftentimes, when we’re talking about misinformation and partisan bias or polarization, we think we all just need to get on the same page information-wise,” Hubeny said. However, the findings from this study show that the penchant to believe false information, or reject the truth, has more complex cognitive origins. It’s not just about “having the facts,” they wrote.
Hubeny noted there aren’t many effective interventions that target the motivated-reasoning side of partisan bias. To seek new approaches, future research should look at why people are motivated to seek out false information related to their partisanship and dig into the specific cognitive mechanisms behind these biases.
“If we can try and pin down exactly what’s going on in motivated reasoning, then hopefully we can develop tools that will be better able to address this source of partisan bias,” Hubeny said.
Reference
Hubeny, T. J., Nahon, L. S., & Gawronski, B. (2026). Understanding partisan bias in judgments of misinformation: Identity protection versus differential knowledge. Psychological Science, 37(1), 43–54.
END
“This is an age-old debate in social psychology … whether something is due to basic cognitive processes or motivational processes,” said Tyler Hubeny, a social psychologist at the University of Texas at Austin. In a new study published in Psychological Science, Hubeny and his colleagues put these two competing theories to the test.
The new study sought to test a common argument that partisan bias arises from differential knowledge. In this theory, researchers frame partisan bias as a byproduct of the information ecosystem, where people of different party allegiances are exposed to different news sources, leading to differing knowledge bases and conclusions. But the flip side—and a more daunting cause of misinformation—is that partisan bias exists because people’s desires influence how they determine whether information is true or false.
“The aim was to try and test that and rule it out and say, well, if we completely take away the differences in prior beliefs, do we still see evidence of partisan bias? And if we do, then it probably is due to that motivational explanation,” Hubeny said.
The new study focused on the United States, where Hubeny and his colleagues recruited over 600 American citizens through an online portal. Instead of using a person’s existing political partisanship, such as Democrat or Republican, the researchers randomly split the participants into Team Spain, Team Greece, or No Team.
“We basically gave them this phony personality test, kind of like the ones you would see on Buzzfeed,” Hubeny explained. The test asked a series of personality questions, which determined the group the participant belonged in. By randomly assigning participants to teams, the researchers were able to eliminate any differences in knowledge that might have existed.
After a participant was given their assigned group, researchers then asked them to judge whether a series of statements were true or false. Some of the statements were favorable to Spain (e.g., “Spain has produced more Nobel Prize winners than Greece”), while others were favorable to Greece. The researchers then analyzed the responses using a method called signal detection theory, which allowed them to measure the participants’ truth sensitivity (how well a participant can distinguish true and false information) and acceptance thresholds (how often they would reject information in general).
The researchers found that even with the random teams, there was a partisan effect in how people determined the truthfulness of the information. This effect was present not because of any differences in knowledge, but because their arbitrary party identity shifted their acceptance thresholds.
“People were more accepting of the information that was congenial toward their randomly assigned team, and less accepting when that information was uncongenial toward their randomly assigned team,” Hubeny said. Therefore, the study supports the theory that partisan bias can exist because of motivational processes, outside of differential knowledge.
These findings have implications for misinformation interventions. “Oftentimes, when we’re talking about misinformation and partisan bias or polarization, we think we all just need to get on the same page information-wise,” Hubeny said. However, the findings from this study show that the penchant to believe false information, or reject the truth, has more complex cognitive origins. It’s not just about “having the facts,” they wrote.
Hubeny noted there aren’t many effective interventions that target the motivated-reasoning side of partisan bias. To seek new approaches, future research should look at why people are motivated to seek out false information related to their partisanship and dig into the specific cognitive mechanisms behind these biases.
“If we can try and pin down exactly what’s going on in motivated reasoning, then hopefully we can develop tools that will be better able to address this source of partisan bias,” Hubeny said.
Reference
Hubeny, T. J., Nahon, L. S., & Gawronski, B. (2026). Understanding partisan bias in judgments of misinformation: Identity protection versus differential knowledge. Psychological Science, 37(1), 43–54.
END