Understanding Partisan Bias in Judgments of Misinformation: Identity Protection Versus Differential Knowledge.

Area of Science:

• Cognitive psychology
• Social psychology
• Political science

Background:

• Partisan bias leads individuals to overaccept identity-supporting information and underaccept opposing information.
• Debate exists on whether this bias stems from motivated reasoning or knowledge differences.
• Previous studies could not distinguish these causes due to pre-existing group knowledge disparities.

Purpose of the Study:

• To investigate the underlying mechanisms of partisan bias in misinformation acceptance.
• To differentiate between identity-protective motivated reasoning and differential knowledge accounts.
• To examine bias using randomly assigned, rather than pre-existing, identities.

Main Methods:

• Two experiments were conducted with 1,411 adult U.S. Prolific workers.
• Participants were randomly assigned to identities.
• Information congenial versus uncongenial to the assigned identity was presented for judgment.

Main Results:

• Participants showed lower acceptance thresholds for information congenial to their randomly assigned identity.
• This effect occurred despite participants having no pre-existing knowledge differences.
• Results indicate bias is driven by factors beyond prior knowledge.

Conclusions:

• The findings support identity-protective motivated reasoning as a key driver of partisan bias.
• Randomly assigned identities effectively isolated the effect of identity protection.
• Implications for combating misinformation interventions are significant.