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The Psychology of Political Bias

Americans are polarized. But what causes political polarization? Why are people inclined to only see their side? The answer is complex and draws from many different social and psychological theories. Here, we’ll focus on the psychological reasons behind individual political biases.

Social scientists have identified two types of thinking, often referred to as System One and System Two. System One thinking occurs when we have quick, emotionally driven responses. When you gag at a horrible smell, raise your upper lip when hearing about government corruption, or see an article by your least favorite columnist, you’re using System One thinking. System Two thinking is used when you engage in slow, thoughtful consideration. Generally, both systems are used when people think about politics. However, System One almost invariably kicks in first, leading to quick, emotional reactions to political information. For the most part, these emotional responses are determined by our political identity.

The problem is that these initial reactions produce bias in our system two thinking. Instead of critically examining both sides of an issue, including our own, system two tries to rationalize and justify our gut response. Thus, instead of developing and refining our political views in light of new information, we often use our rational thinking to reaffirm preexisting beliefs—a tendency that makes it difficult to hear the other side’s argument.


Hollingworth, C., & Barker, L. (2018). System 1 and System 2: Two Modes of Thinking. Research World.  


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