"The Party told you to reject the evidence of your eyes and ears. It was their final, most essential command."
- George Orwell, 1984 

In Orwell’s famous novel, 1984, he described how a totalitarian government could manipulate the minds of its citizens through a state of perpetual war, government surveillance, propaganda, and aggressive police. The main protagonist in the book was responsible for constantly revising the historical record (i.e. actively creating falsehoods) to ensure it was always consistent with the current party line. The party ultimately demanded that citizens abandon their own perceptions, memories, and beliefs in favor of party propaganda. In our paper, The Partisan brain: A value-based model of political belief (Van Bavel & Pereira, 2018) we examine how identification with political parties and leaders can shape our beliefs and lead us to reject factual evidence. 

There is extensive evidence that political affiliations influence attitudes, judgments, and behaviors. While it is widely accepted that identification with a political party—known as partisanship—shapes political judgments, such as voting preferences or support for specific politics, it is less obvious why political affiliations might shape perceptions of facts. For example, US Democrats and Republicans strongly disagree on scientific facts, such as climate change, economic issues—such that Republicans show much more optimistic economic expectations than do Democrats after President Donald Trump’s election in 2016—, and even facts that have little to do with political policy, such as crowd sizes. For instance, Mr. Trump supporters were more likely than supporters of his political opponent (Hillary Clinton) or non-voters to mistakenly identify a photo of President Barack Obama’s 2009 inauguration as being from Mr. Trump’s 2017 inauguration. These examples make it clear that people do not require an authoritarian state to ignore their own eyes and ears: partisan identities bias a broad range of judgments, even when presented with facts that contradict them. 

The influence of partisan identities can threaten the democratic process, because a healthy democracy requires and assumes that citizens have access to reliable knowledge in order to participate in the public debate and make informed choices. In our paper, we describe how the social identification can leads people to value party dogma over truth. Specifically, we introduce a value-based model of belief that explains (1) why people willingly align their beliefs with political parties and (2) how partisan identities alter information processing from reasoning, to memory, implicit evaluation, and even perception. These psychological processes help explain the recent surge of misinformation, conspiracy theories, and fake news, as well as why party affiliation has such a strong impact on people’s judgments that they often abandon their cherished values and beliefs in favor of party loyalty. We also discuss strategies for de-biasing information processing to help create a shared reality across group divides. In addition to changing the goal to value accurate information, we introduce the idea of a process based intervention—targeted the stage in information processing in which bias is entering. The issue of partisan beliefs is particularly relevant during the current global pandemic, when aligning one’s beliefs with science is a matter of life and death and a sense of shared reality can reduce everyone’s risk of infection.