We now have decades of research suggesting—if not proving—“the ubiquity of emotion‐​biased motivated reasoning,” reasoning that is qualitatively different from the kind operating when subjects are engaged in “cold reasoning,” where the subjects lack a “strong emotional stake” in the subjects at issue. Coupled with a growing literature on the startling character and extent of political ignorance, the current state has dire implications for human freedom. The stakes are high: in their 2018 study of why and how partisanship impairs the brain’s ability to process information objectively, NYU researchers Jay J. Van Bavel and Andrea Pereira note that “partisanship can alter memory, implicit evaluation, and even perceptual judgments.” One recent study, published last fall by a team from Berkeley, Stanford, and Johns Hopkins, set out to better understand how partisan biases develop in the brain. The researchers had subjects watch a series of videos, using fMRI to explore the “neural mechanisms that underlie the biased processing of real‐​world political content.” The results showed that partisan team members process identical information in highly biased and motivated ways. The researchers locate this neural polarization in the part of the brain known as the dorsomedial prefrontal cortex, a region associated with understanding and formulating narratives. The study also found, perhaps unsurprisingly, that to the extent a given participant’s brain activity during the videos aligned with that of the “average liberal” or “average conservative,” the participant was more likely to take up that group’s position.

The study accords with years of previous research showing that partisans’ opinions on important social, political, and economic issues are affected by subconscious brain processes—processes of which they’re neither aware nor in control. This ought to be deeply concerning to everyone who belongs to a political team: processes are taking place in your brain, underneath or beyond the level of direct awareness, that are informing your conclusions about important social and political issues. To reflect on this for even a moment should fill anyone who aspires to critical thinking or rationality with a kind of dread, for loyalty to the team seems to be overriding the higher faculties of the mind. But, the authors are careful to note, it’s important not to interpret these results as pointing to some kind of determinism, whereby we can’t choose how to think or what we believe. As one of the study’s authors, Stanford psychologist Jamil Zaki, says, “Critically, these differences do not imply that people are hardwired to disagree.” Rather, these neural pathways seem to be carved largely by the kinds and sources of the media we consume. From the data yielded by such research, among many other similar studies, a picture begins to emerge of partisanship as a kind of mind poisoning, an infection that leads to serious and, importantly, measurable cognitive impairment. Evidence suggests that, under the influence of partisanship, we can’t even understand our own thoughts and opinions.

In another important, recent experiment, researchers wanted to understand the relative accuracy of participants’ introspective constructs. The researchers set out to gauge people’s ability to understand their own choices, to see clearly “the elements of internal argumentation that lead to [their] choices.” In particular, the researchers wanted to know how subjects would deal with choices that had been manipulated—that is, whether subjects would “notice mismatches between their intended choice and the outcome they are presented with.” Would subjects recognize that something was off? If they failed to notice the manipulation, would they offer justifications for choices they had not even made? The assumption is that subjects who fail to notice the mismatches must not really understand the reasons for their choices or “the internal processes leading to a moral or political judgment.” The results revealed a conspicuous “introspective blindness to the internal processes leading to a moral or political judgment.” People didn’t seem to understand why they had made the decisions they’d made (or had not made), though some exhibited what the researchers call “unconscious detection of self‐​deception”—these subjects were unable to detect the manipulations of their answers, but they did register lower confidence in the manipulated choices, which the authors suggest points to “the existence of a neural mechanism unconsciously monitoring our own thoughts.”

Once one has chosen and joined a team, she has very little control over her own thoughts. When they are introduced, new data are distorted, misinterpreted, or discarded based on their consistency with what we may describe as a program running in the background: partisanship leads the team member into a cognitive position of unconscious self‐​deception. Few of us, if fully understanding this phenomenon, would choose it for themselves—at least that’s the hope of many who study this area. As the authors observe, “reflecting on our beliefs may help to develop free societies.” They suggest that if citizens better understood the brain mechanics of the cognitive impairment and self‐​deception brought on by partisanship, they’d be positioned to make better decisions. Research has shown that “reflecting on how we make decisions leads to better decisions.”

Similar research on self‐​deception in politics has also confirmed the presence of the Dunning‐​Kruger effect (to summarize, people think they know a lot more than they actually do). Further, the effect is exaggerated within the context of politics, with low‐​knowledge participants describing themselves as even more knowledgeable than usual once partisanship is made a conspicuous factor. Vitor Geraldi Haase and Isabella Starling‐​Alves posit that the kind of self‐​deception that is such “a major characteristic of political partisanship…probably evolved as an evolutionary adaptive strategy to deal with the intragroup‐​extragroup dynamics of human evolution.” Objective truth, meaning roughly an accurate model of reality, is not important, at least not anywhere near as important, as conformity and indeed submission, which we may associate with social reality.

Whatever its flaws, evolutionary psychology offers us several promising leads on the question of just why the brain isn’t able to perform on partisanship. This notion of social reality is an important clue. At this juncture, it is important to underline the fact that when we speak of partisanship, we are not speaking of ideology; the relationship between partisan identification and political ideology is complicated, the connection between the two not particularly strong. Ideologues tend to think systematically, and the philosophical contents of their beliefs are deeply important to them. What is important to the partisan is not what she believes, but that she aligns her beliefs with those of her team or in-group—or else, as may be the case, that she is loyal to and supportive of the party group despite any real or perceived ideological nonconcurrences. Americans tend to vastly overestimate the differences in political ideology and policy preferences between Democrats and Republicans. In fact, most Americans are not at all ideological, can’t describe ideologies accurately (as their proponents would describe them), and have almost no information on either the history of ideas or the empirical evidence that bears on particular political or policy questions. Interestingly, partisanship doesn’t necessarily seem to be about politics in the normative or philosophical sense, as “people place party loyalty over policy, and even over truth.” There are actually relatively weak correlations between partisan identity and concrete policy preferences. “[P]artisan affect is inconsistently (and perhaps artifactually) founded in policy attitudes.” Indeed, strong partisanship is necessarily an impediment to ideological thinking insofar as ideology is predicated on an integrated and consistent approach to policy questions, as against the blind, team‐​rooting approach associated in the literature with partisanship. Ideological people, whatever their flaws, hold political actors and government bodies to account. Partisans change positions readily and shamelessly, depending on anything from who is living in the White House, to the vagaries of party leaders, to what is perceived as popular at the moment. Further, individual Americans’ political opinions are remarkably unstable over time, vacillating between glaring contradictions, relying on a confused amalgam of elite opinions. Partisanship as we know it rather seems to be a holdover from humankind’s history of tribal loyalty, with “selective pressures hav[ing] sculpted human minds to be tribal.” That is, evolution selected for just the kinds of cognitive biases we find in partisans on both sides today (importantly, neither “team” is immune).

A recent paper published by the American Psychological Association suggests that from a cognitive and psychoneurological standpoint, partisans of the left and right are much more like each other than they are like nonpartisans. As study co‐​author Leor Zmigrod writes, “Regardless of the direction and content of their political beliefs, extreme partisans had a similar cognitive profile.” Specifically, partisans of all stripes show lower levels of cognitive flexibility; importantly, even when processing information that has no political character, they are more dogmatic, less adaptable, and less able to complete tasks that require an “ability to adapt to novel or changing environments and a capacity to switch between modes of thinking.” Partisanship quite literally makes one dumb—or is it that dumb people are just more likely to be committed partisans? Zmigrod is careful to point out that the study can’t give us the answer to that question, that we would need longitudinal studies in order to better understand the causal direction and causal phenomena at play. As soon as partisanship is introduced, as soon as a question mentions a politician or political party, subjects are unable to accurately assess basic facts. Indeed, remarkably, tinging a question with a political shade renders many subjects unable to answer a simple question even when they are given the answer. Relatedly, studies have shown that one’s political affiliations even affect her ability to perform basic math: given an operation that yields a statistic contradicting a subject’s partisan view, the subject will tend to question the result rather than updating based on the evidence or attempting to reconcile the new information with her politics.

In a groundbreaking study published last summer, a team of researchers led by the University of Exeter’s Darren Schreiber attempted to address the lack of brain imaging research specifically aimed at better understanding nonpartisans, a group that has been neglected as almost all such research has focused on the differences between the brains of partisans of the left and right. The study found that nonpartisans’ brains are different from those of their brainwashed brethren, particularly in “regions that are typically involved in social cognition.” It may be that the next stage in human evolution will involve rewiring our brains to accept the fact that current groups are artificially and arbitrarily defined—that all human beings are one people. For just as there is harmful, toxic tribalism, there is also socially beneficial, cooperative, cosmopolitanism. As social policy expert Elizabeth A. Segal writes, “Ultimately our goal should be to build the tribe we all belong to: that of humanity.” Libertarians take this lesson quite seriously, for we tend to see ourselves as part of a common global community of connected individuals who are perfectly capable of dealing with one another through peaceful and mutually‐​beneficial interactions. We celebrate social, cultural, religious, and linguistic differences as the spice of life rather than see them as dividing lines or impediments to willing collaboration. If we can understand and think clearly through partisanship, we can begin to build a freer world based not on arbitrary divisions and compromised reasoning, but on mutual respect and renewed emphasis on rigorous critical thinking.

This article was originally featured at Libertarianism.org and is republished with permission.