The Neurological Basis Driving the Two-Party System

Since the beginning of the United States, our nation has had a strong tendency to be politically divided into conservative and liberal parties. Conservatives generally hold traditional values and believe in the empowerment of the individual over the government. On the other hand, liberals support socially progressive policies and promote social welfare. The tensions resulting from the differences between these two groups have made civilized politics difficult to achieve. It is difficult to bridge the gap between the parties and rightfully so: the two sides have been proven to be neurologically developed differently, changing how they see the world.

On the whole, conservatives prioritize security, predictability, and authority, while liberals desire novelty, nuance, and complexity. In order to further explore these differences in priorities, a trio of political scientists at the University of Nebraska-Lincoln conducted experiments to research the neurological composition between conservatives and liberals. John Alford, Kevin Smith, and John Hibbing put participants in a magnetic resonance imaging machine and presented them with identical images that triggered social and emotional processing, noting differences in their brain composition. Specifically, the areas that process social and emotional information had important distinctions: they found that liberals tended to have a larger volume of gray matter making up the anterior cingulate cortex, while conservatives tended to have a larger amygdala. The anterior cingulate cortex is connected to many regions in the brain, including the orbitofrontal cortex, the basal ganglia, and the insula, so it plays an important role in the functioning of the brain between various regions. Moreover, it is involved in many cognitive functions, such as decision-making. So, liberals tend to have a stronger ability to detect errors and resolve conflicts. The amygdala on the other hand controls how the body feels emotions and perceives them in others, which gives conservatives the advantage of being able to regulate their emotions and evaluate threats.

Scientists then sought to connect the underlying cognitive processes resulting from differing neurological structures to differences in political beliefs. An experiment conducted by Ingrid Haas studying how we process political information showed that liberals paid more attention to incongruent information given, that is, positions taken by either party that are not compatible with their normal beliefs. Additionally, their brains showed more activity in the insula and the anterior cingulate cortex, which are important in helping people form and alter their attitudes. In addition, a study that scanned the brains of more than 36 conservative and liberal participants while viewing videos concerning controversial immigration policies, such as the building of the U.S.-Mexico border wall and the DACA program which protects young illegal immigrants from deportation, suggested that there is a neural basis to partisan biases and certain language can drive that polarization. The differences in response are attributed to the dorsomedial prefrontal cortex, the part of the brain that tracks and makes sense of narratives. Overall, the study suggested that political messages use emotional language that drives partisans to interpret the same message in opposite ways, contributing to increasing polarization.

Partisanship plays into an aspect of political neuroscience called motivated reasoning, the innate human desire to be perceived as a good-hearted person living in a fair society. It is a concept where people will justify their opinions or actions despite being presented with conflicting evidence. The role of partisanship is also influential as it can lead to rationalizing long-standing inequalities or injustices in order to justify opinions; in other words, system justification. The neurological processes governing the functioning of system justification is the amygdala. Those with larger amygdala volumes are more likely to perceive the current political system as just and want to avoid change and protest, resulting in more conservatism. Moreover, a study at University College London showed that the amygdala is vital to the processing of fear: those with larger amygdalas are more sensitive to fear. Therefore, conservatives are heavily influenced by their desire to satisfy psychological needs to understand the complexities of the world, and to regulate their uncertainty and fear of a changing political climate. They subscribe to their beliefs because it helps them reduce this fear, anxiety, and uncertainty—avoiding change and disruption, justifying the current order of politics. Often, this may justify inequality among certain groups and individuals. On the other hand, a larger anterior cingulate cortex allows for more uncertainty to be tolerated because it monitors such uncertainty. Thus, people with larger anterior cingulate cortices are more prone to accepting liberal views.

In fact, a 2018 study showed that conservatives had a weaker tolerance for looking at disturbing images and were quicker to look away than their liberal counterparts. This may seem like an insignificant difference, but a human’s gut reaction of disgust can impact how they see people who are different from them. Though a strong gut reaction of disgust has evolved to be a helpful tool for survival as it helps humans avoid impure pathogens, it also impacts how they see people who aren’t like them like immigrants or foreigners, and this feeling is intensified by their natural tendency to be more scared of “the other” because it’s not familiar to them. Interestingly enough, another study from the 1980s showed that conservatives preferred simple paintings, familiar music, and unambiguous texts and poems while liberals enjoyed cubist and abstract art. This supports the conclusion that conservatives prefer familiarity while liberals embrace ambiguity and change.

These findings suggest that the development of the two-party system to its current division between generally conservative Republicans and liberal Democrats has been encouraged by neurological differences in brain composition. Conservatives tend to value consistency over change and liberals vice versa due to a strong influence over the brain from either the amygdala or the anterior cingulate cortex. Though the effectiveness of the two-party system is controversial, the innate tendencies of human evolution support the creation and continuation of it.