PDF Summary:The Ideological Brain, by Leor Zmigrod

Why do some people cling to extreme beliefs while others remain open-minded? In The Ideological Brain, Cambridge neuroscientist Leor Zmigrod reveals the surprising neural underpinnings of ideological thinking, showing how our brains not only shape our political and religious beliefs, but are shaped by them in turn. Zmigrod’s research demonstrates that ideology isn’t just about what you believe—it’s about how your brain processes information.

To unpack these neuroscientific insights, we’ll examine how ideological thinking works, how it rewires the brain, and why some people are more susceptible to it than others. We’ll also explore Zmigrod’s tactics for cultivating mental flexibility and resisting the allure of dogma in the real world—where her findings might help us create more productive dialogue across ideological divides. Along the way, we’ll explore how these ideas connect to evolutionary psychology, what intelligence in other species reveals about cognitive flexibility, and how we can balance intellectual humility with principled values.

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The Brain You Think You Have Versus the Brain You Have

Other researchers agree with Zmigrod that there’s often a disconnect between how we perceive our thinking style and how our brains process information below the level of our conscious awareness. For example, studies show that how cautiously people’s brains approach the tasks researchers use to study decision-making bears no relationship to how impulsive they report themselves to be. Even people who describe themselves as highly impulsive don’t necessarily make hasty decisions in cognitive tests.

This self-awareness gap is even more pronounced in ideologically extreme individuals. As Zmigrod has found, people with more dogmatic or extreme views on both the political left and right exhibit worse metacognitive awareness than those with moderate views: They’re less able to accurately judge their own performance and cognitive processes. This suggests we should be cautious in drawing conclusions about our cognitive styles based on our personality traits or political views: Our self-perception isn’t always aligned with our brain’s actual information processing style.

Factor #3: Brain Structure Influences Ideological Preferences

In addition to people’s behaviors and beliefs, Zmigrod’s research examines physical brain structures, particularly the amygdala, a brain region involved in processing emotions and detecting threats. Studies have found that people with more conservative ideologies often have larger amygdalae, correlating with heightened vigilance toward potential threats. This might explain why conservative ideologies, which often emphasize threats to and the preservation of traditional values, appeal to those with enhanced threat-detection systems.

However, this raises what Zmigrod calls the “chicken-and-egg problem”: Do people with larger amygdalae gravitate toward conservative ideologies because their brains are already primed for threat detection? Or can immersion in certain ideologies alter our emotional biochemistry and lead to structural brain changes? She says this question remains an active area of research.

(Shortform note: Scientists and statisticians note that correlation doesn’t imply causation, as Zmigrod cautions about the correlation between amygdala size and political ideology. People with anxiety or depression often show enlarged amygdalae, suggesting that emotional states influence brain structure. People with bigger social circles also tend to have larger amygdalae to help with social processing and relationship management. This helps contextualize the “chicken-and-egg problem”—while brain structure may influence ideological tendencies, our ideological environments and responses to them may also reshape our neural architecture, creating a feedback loop between biology and belief.)

Factor #4: Stress Makes Everyone More Ideologically Susceptible

Environmental factors also influence your susceptibility to ideological thinking. Zmigrod notes that stress can significantly impact cognitive flexibility. Under stress, even typically flexible thinkers may become more rigid and thus more receptive to ideological narratives. This helps explain why periods of societal stress—economic downturns, pandemics, or political instability—often coincide with rises in extreme ideological movements. Peoples’ neural responses to stress temporarily diminish their capacity for nuanced thinking, making the certainty offered by rigid ideologies more appealing.

(Shortform note: Sacrificing flexible thinking for the safety of certainty seems to be a survival strategy that’s evolved in different branches of the animal kingdom. For example, though octopuses’ lineage diverged from ours 500 million years ago, they have remarkable cognitive flexibility, using their distributed nervous system—with three-fifths of their neurons located in their eight arms—to solve complex problems, adapt to changing environments, and learn through observation. Yet, like humans, octopuses become less cognitively flexible under stress, even though they lack stress hormones like ours and have entirely different physiological responses to stress)

How Does Ideology Rewire Your Brain?

Ideological thinking doesn’t just reflect your existing mental tendencies. It actively reshapes how your brain functions by altering your neural pathways, cognitive patterns, and physiological responses. Zmigrod explains that this transformation happens because of neuroplasticity, your brain’s ability to reorganize itself by forming new neural connections. When you’re repeatedly exposed to ideological rules, rituals, and ways of thinking, your brain physically changes. Neural pathways that support ideological habits strengthen through repetition, while alternative mental pathways weaken from disuse.

Think of it like a path through a forest: The more a particular route is traveled, the more defined it becomes. Conversely, unused trails gradually disappear. In the same way, your ideological habits carve pathways in your brain that become increasingly difficult to deviate from.

(Shortform note: In The Brain That Changes Itself, psychiatrist Norman Doidge delves deeper into how neuroplasticity works on the biological level. Basically, he says, the brain is made up of neurons, or nerve cells, which send signals to each other across tiny spaces called synapses. Neurons can send and receive two types of messages: signals that cause other neurons to fire and those that make other neurons less likely to fire. If a specific type of signal is sent between neurons again and again, a pathway forms, making that firing pattern more likely in the future. This is why repetition—using the same neural pathway—makes thoughts or actions more reflexive.)

Let’s look at three effects ideology can have on your brain:.

Effect #1: Ideology Impairs Your Information Processing

One of the most powerful consequences of ideological thinking is how it changes the way you process information. Zmigrod’s research reveals that ideological thinking shifts brain activity away from your deliberative prefrontal cortex (the brain region responsible for complex decision-making and rational thought) toward deeper, older regions of the brain (like the striatum) that govern routine behaviors and emotional responses.

(Shortform note: When you adopt ideological thinking patterns, your brain doesn’t turn off the prefrontal cortex (PFC), but subordinates its influence to more automatic processes. Deeper brain regions are excellent at processing familiar patterns and emotional content, but they lack the PFC’s capacity to evaluate nuanced evidence and update beliefs, which, when the PFC is dominant, help us maintain cognitive flexibility and quickly correct errors in our thinking. When activity shifts away from the PFC to the brain’s subcortical regions, information processing becomes more rigid and reflexive, with less conscious awareness than the PFC’s deliberative processes. This makes ideological reactions feel instinctive rather than chosen.)

Zmigrod explains that when information processing shifts away from the prefrontal cortex and toward more automatic brain regions, this produces several related effects that make it increasingly difficult for you to process new information objectively and learn from mistakes. These effects include:

1. Selective perception: You begin to notice and prioritize information that confirms your existing beliefs, and you increasingly filter out contradictory evidence without even noticing that you’re doing so.
2. Slower evidence processing: You have a harder time taking in and using new information. Your brain literally processes evidence more slowly, making it difficult for you to update your understanding when faced with new facts.
3. Difficulty detecting errors: Ideological thinking impairs your ability to recognize when you’re making mistakes or engaging in faulty reasoning. You may not only miss your errors but also perceive yourself as more decisive and clear-thinking than others.
4. Distorted memory: Ideology can function as a filter not just for new information, but for your memories as well, retroactively reshaping your perception of the past to align more closely with your current beliefs.

What the Shift Away From the Prefrontal Cortex Does to the Brain

The four effects of ideological thinking on our information processing ability—which emerge from the shift in brain activity from the deliberative prefrontal cortex to more automatic subcortical systems—help explain why less rational forms of thinking take hold.

Selective perception: When you adopt an ideological viewpoint, your brain begins filtering information before you even consciously process it. This happens because ideology activates neural pathways that selectively enhance the processing of information that’s consistent with your assumptions and expectations. This is why two people can witness the same event, yet “see” completely different things.

Slower evidence processing: Ideological thinking impairs your brain’s ability to efficiently integrate new evidence, especially when that evidence contradicts your beliefs. This selectiveness happens because as the PFC steps back, your working memory capacity takes a hit—your capacity to hold information in your mind is reduced.

As a result, your brain prioritizes processing information that fits with your existing ideas, and it takes significantly longer to process perceptual data that doesn’t fit neatly into your mental frameworks. This is why presenting “facts” rarely changes people’s ideological beliefs: The ideological brain doesn’t have the capacity to process contradictory information as quickly or effectively as information that’s congruent with current beliefs.

Difficulty detecting errors: When your brain is in an ideological state, its error-detection systems function poorly. Studies of error-related brain activity show that ideological thinking dampens the neural signals that normally help you recognize when you’ve made a mistake, to an extent that’s similar to the impairment seen in people with damage to error-detection regions in the medial prefrontal cortex (mPFC). This explains why people often double down on ideological beliefs even when presented with clear evidence of their errors.

Distorted memory: Ideology doesn’t just distort our reasoning about new information but also reshapes our memories about what we’ve experienced in the past. People are more likely to “remember” events that never happened if those false memories align with their political narratives. This occurs because memory isn’t a perfect recording but a reconstruction that’s influenced by your current beliefs. Your brain fills in gaps with information that feels consistent with your ideological framework, creating memories that feel authentic but are incorrect.

Effect #2: Ideology Numbs Your Emotional Responses

A second consequence of ideological thinking is that it can alter your emotional and physiological reactions to information and events, particularly those involving others’ suffering. Zmigrod cites a study where participants with strong “system-justifying beliefs” (in this case, beliefs that economic inequalities are natural and good) showed muted responses to videos of homeless people describing their hardships. Their bodies didn’t react: They showed no difference in heart rate or skin conductance when watching these videos versus videos of coffee beans being processed. (Shortform note: System justification theory proposes that we’re motivated to defend existing social and economic systems, even when they disadvantage us.)

This emotional numbing happens because their ideology provides an explanation that justifies the suffering they’re seeing. For people who believe strongly that economic systems are fair and that inequalities result from people’s individual choices rather than from systemic problems, the sight of homeless people doesn’t register as a moral injustice that requires an emotional response. Their ideology effectively acts as an emotional buffer, preventing the empathetic reaction that would otherwise occur when seeing another person’s suffering.

(Shortform note: The emotional numbing Zmigrod describes doesn’t just reduce empathy: It creates a feedback loop where ideology strengthens itself by reducing the likelihood that someone will question their beliefs. Research shows that people who believe economic systems are fair don’t perceive the people who suffer under these systems, like those experiencing homelessness, as fully human. Their brains disengage from evidence that others are suffering, which would contradict their belief that society is meritocratic. This protects them from the discomfort of questioning their worldview. So they see themselves as rational even as they fail to see evidence of systemic unfairness—and miss how this unfairness hurts others.)

Zmigrod notes this pattern extends beyond this one example: When you adopt an ideology that categorizes others as out-group members or justifies their suffering, your typical emotional and physiological responses to human pain—responses that would normally trigger empathy—are reduced. When you encounter information that aligns with your ideological beliefs, your body tends to show increased physiological arousal. Conversely, when confronted with information that contradicts your ideological beliefs, you experience negative emotions like fear, disgust, and anger, which can lead to defensive reactions and a strengthening of your existing beliefs.

How Our Beliefs About Gender Affect How We Perceive Others

Zmigrod’s research reveals that ideology doesn’t just influence what we think: It changes how we perceive other people. For example, when we adopt ideological thinking about gender, it alters our ability to process information about people who don’t conform to our expectations. One reason transgender, nonbinary, and gender-nonconforming people face widespread bias is that our brains are wired to categorize people by gender. But this split-second categorization is disrupted when we encounter someone who challenges our beliefs about gender, illuminating why trans people (for example) face bias even from people who consciously support their rights.

This split-second categorization leads to “disfluent processing,” which manifests in two key ways: First, there’s perceptual disfluency, which occurs when someone’s appearance doesn’t match our expectations. This happens at a basic visual processing level, where people’s brains categorize gender-ambiguous faces less accurately than stereotypically gendered faces. This processing difficulty plays a role in misgendering people.

Second, there’s conceptual disfluency, when the very idea of someone being transgender or nonbinary challenges our existing ideas about gender. Our brains have well-developed ways to quickly and automatically identify cisgender men and women, but these can be underdeveloped or contradictory when categorizing someone who’s transgender or gender nonconforming.

The amygdala plays a crucial role in this process. The amygdala helps the brain evaluate the trustworthiness of a person’s face within milliseconds, even before we’re consciously aware we’re looking at a face. When we have trouble making sense of someone’s gender, this difficulty may trigger the amygdala’s threat-detection system, which generates feelings of distrust. This may help explain why transgender individuals are sometimes perceived as deceptive, despite no intention to deceive. Zmigrod shows that ideology can strengthen these automatic responses by creating rigid patterns that resist updating.

Effect #3: Ideology Creates a Paradoxical Relationship with Order and Chaos

A third consequence of ideological thinking is what Zmigrod identifies as the “rigidity-chaos paradox,” which describes a contradiction in how ideologically rigid thinkers behave. In her experiments, Zmigrod discovered that the same people who showed cognitive inflexibility and rigid thinking in laboratory tasks often described themselves as thrill-seekers who make impulsive decisions. Despite being slow and methodical when processing evidence at a neurological level, these dogmatic individuals not only see themselves as quick and decisive, but they also tend to make more impulsive decisions in real-world situations. This creates a disconnect between their slow cognitive processing and their hasty actions.

Other researchers found a similar pattern in children raised in authoritarian households. These children simultaneously showed “disintegration and rigidity”: They were obsessed with rules and order but also expressed a fascination with chaos, upheaval, and catastrophe. This paradox helps explain why political extremists often demand strict law and order while at the same time advocating for revolutionary upheaval or apocalyptic scenarios. A dogmatic person might insist on rigid moral codes and social structures while also being drawn to violent, chaotic solutions to perceived problems.

Zmigrod suggests this paradox emerges because the dogmatic mind struggles with efficient information processing. Since making sense of complex reality is cognitively taxing for rigid thinkers, they’re drawn to simple, absolutist explanations that impose order—this kind of structure is comforting and less cognitively demanding. At the same time, they’re attracted to dramatic, destructive solutions that use chaos to tear down existing systems they don’t agree with—since this would reduce the complexity of the real-world problems they’re struggling to grapple with.

The Fine Line Between Principle and Rigidity

Larry David’s character on Curb Your Enthusiasm walks a fine line between standing up for his principles and veering into cognitive rigidity. Larry frequently calls out violations of unwritten social rules, confronting people who attempt to “chat and cut” in lines or “pig parkers” who take two parking spaces. Such confrontations emerge from his commitment to certain principles: what philosophers might call his loyalty to the social contract. Yet Larry’s inability to adapt to changing social norms—and his refusal to let go of minor grievances—show how ideological thinking can impair cognitive flexibility. No matter how many times Larry’s confrontational approach backfires, he never learns to adjust his behavior.

This pattern reflects Zmigrod’s observation that ideologically rigid thinkers often display a paradoxical relationship with order and chaos. In the show, Larry insists on rigid social norms while disrupting social harmony. He wants a world of perfect order but creates chaos in pursuit of it. The character offers us a mirror: How often do we become so attached to our principles that we lose the flexibility for harmonious social interaction? When does principled thinking cross the line into ideological rigidity? The comedy comes from recognizing this tension in ourselves, even as we laugh at Larry.

How Can We Cultivate Flexible Thinking?

After exploring how ideology can constrain our thinking, Zmigrod turns to the question of how we might protect ourselves from it. Her research points to cognitive flexibility as our best defense—the ability to adapt our thinking and consider multiple viewpoints. Cognitive flexibility acts as a protective barrier against extremism by preventing you from adopting overly rigid and dogmatic beliefs. When you can fluidly consider different perspectives, you’re less likely to become entrenched in a single ideological viewpoint. This flexibility fosters intellectual humility, the awareness that your beliefs may be biased, and the willingness to revise them when faced with new evidence.

Let’s look at a few of Zmigrod’s methods for cultivating cognitive flexibility.

Method #1: Build an “Anti-Ideological Brain”

Zmigrod envisions what she calls an “anti-ideological brain”—a mind that actively and creatively rejects the temptation of dogma. Such a mind is characterized by traits that allow you to engage with ideas without becoming possessed by them—so you can maintain your intellectual autonomy even while participating in collective movements or communities. These traits include:

• Intellectual humility: Acknowledging the limits of your knowledge and that your views might not be correct.
• Tolerance for ambiguity: Embracing nuance and complexity rather than demanding simplistic black-and-white explanations.
• Evidence-based belief updating: Willingly revising your beliefs when presented with credible contradictory information.
• Perspective-taking abilities: Actively considering multiple viewpoints, even those that challenge your existing beliefs.
• Balanced emotions: Regulating your emotional responses to allow for more objective information processing.

How to Start Building an Anti-Ideological Brain: Focus on Intellectual Humility

Of the traits Zmigrod ascribes to the anti-ideological brain, intellectual humility seems to be the foundation from which the others emerge. Intellectually humble people show tolerance for ambiguity by embracing nuance. They naturally engage in evidence-based belief updating: Studies show they’re attentive to the quality of evidence and willing to revise their views. They have better perspective-taking abilities because they spend time considering opposing viewpoints and are motivated to understand why others disagree. Finally, they demonstrate more balanced emotional responses during disagreements, since they’re less defensive and are able to maintain close relationships even during conflicts.

If you want to cultivate intellectual humility, learn to hold your beliefs with the appropriate level of confidence: neither clinging to them too rigidly nor abandoning them too easily. Practice questioning your own opinions by asking yourself what evidence might change your mind. Deliberately seek to understand viewpoints that challenge your perspective, and when disagreeing with others, focus on following their reasoning rather than formulating your counterarguments.

Zmigrod offers several strategies you can use to build an ideology-resistant brain:

Strategy #1: Practice Mindfulness

Mindfulness meditation strengthens prefrontal attentional control and emotional balance, countering the tendency of ideologies to shift brain activity away from the more deliberative regions. By developing greater awareness of your thoughts and emotions, you create space between external stimuli and your responses, reducing the reactive thinking patterns that fuel ideological rigidity.

Strategy #2: Seek Novel Experiences

Actively pursuing mind-expanding experiences creates new neural connections that support cognitive flexibility. Zmigrod says that when you expose yourself to diverse perspectives, cultures, and ideas, you help prevent the narrowing of thought that characterizes ideological thinking. This might involve reading books outside your comfort zone, traveling to new places, or engaging in conversations with people who think differently than you do.

Strategy #3: Question Your Assumptions

Consciously examining your ideological assumptions and entertaining alternative viewpoints can update habitual patterns of thought. Zmigrod suggests regularly asking yourself questions like: “What evidence would change my mind about this belief?” or “How might someone with a different background view this situation?”

Buddhism and the Anti-Ideological Brain

Zmigrod’s practical approaches to maintaining your intellectual autonomy while you engage with social and political ideas parallel Buddhist practices aimed at freeing the mind from rigid thinking. First, mindfulness meditation has deep roots in Buddhist tradition, where it serves precisely the purpose Zmigrod describes: creating space between what we experience and how we respond to it. The practice strengthens the skill Buddhists call “non-attachment,” which lets you observe your thoughts without automatically identifying with them. Second, Buddhism emphasizes the value of stepping outside your own viewpoint to recognize how all perspectives, including your own, arise from particular conditions and are inherently limited.

Finally, the practice of questioning your assumptions is central to Buddhist training. Buddhism teaches that you need to create mental distance between yourself and the cultural ideas and social identities that might otherwise seem to define you. This lets you participate in social or political movements while still thinking independently. Rather than being subsumed by group ideology, you can engage with collective action while recognizing what Buddhists call “interdependence,” the understanding that all beings and perspectives are interconnected, with no perspective existing in isolation.

Method #2: Create Environments That Nurture Flexibility

The second way Zmigrod says you can cultivate cognitive flexibility is through your environment. The environments where you spend your time play a crucial role in fostering or hindering cognitive flexibility. So, as much as possible, spend time in surroundings that encourage open-mindedness, critical thinking, and intellectual humility. This applies to everything from family dynamics and educational settings to workplace cultures and media ecosystems. Zmigrod notes that children raised in authoritarian environments internalize habits of obedience and conformity, while those raised in families that foster imagination and empathy develop greater cognitive flexibility.

(Shortform note: The most cognitively flexible animal brains belong to highly social species, suggesting that participation in complex social environments may be key for cognitive flexibility. Whales, dolphins, and even birds like crows and ravens, have a remarkable mental flexibility that evolved separately from ours. These animals all evolved to live in complex social groups and have to track relationships, communicate, and adapt to change. That this is common among intelligent species hints that the most effective way to improve your own cognitive flexibility might be to cultivate relationships and practice your social cognition skills—that is, your brain’s ability to negotiate the complexities and nuances of the social world.)

Method #3: Balance Strong Convictions with Open-Mindedness

Zmigrod doesn’t advocate abandoning all convictions or principles in your effort to keep yourself from falling into patterns of ideological thinking. Rather, she argues for a minimalist form of liberalism defined by an openness to new evidence and a willingness to participate in productive debate with others. The challenge is to maintain strong ethical foundations and a sense of purpose while avoiding dogmatic rigidity. Flexibility doesn’t mean the absence of beliefs, but rather holding beliefs in a way that remains open to refinement, nuance, and growth.

(Shortform note: Zmigrod’s advocacy for open-mindedness echoes concerns from across the political spectrum about how ideology can warp our thinking. For example, former libertarian leader Jerry Taylor abandoned his ideological commitments after realizing they led him to dismiss climate science evidence that contradicted his political views. He now argues for what he calls “moderation with a purpose”—maintaining strong ethical principles but being willing to adapt those principles to different situations. This aligns with Zmigrod’s “minimalist liberalism.” Both suggest we should hold firm values while recognizing that different ethical considerations may be more important in different contexts, requiring thoughtful case-by-case judgment.)

Method #4: Protect Yourself During Times of Stress

Zmigrod cautions that even typically flexible thinkers become more rigid under stress. During periods of personal or societal turmoil, when our cognitive resources are taxed, we all become more vulnerable to ideological thinking. Recognizing this vulnerability is essential. By understanding that stress diminishes your cognitive flexibility, you can be more intentional about creating space for deliberation and reflection during difficult times when rigid ideological thinking is most tempting.

(Shortform note: Writer and activist Rebecca Solnit suggests an alternative to the isolated individualism that fuels ideological thinking in stressful times. She emphasizes the power of community and mutual aid during crises. In A Paradise Built in Hell, she reports that people often find unexpected joy and purpose in helping others during difficult times, forming deep connections that outlast the crisis itself. By focusing on what you can offer others—joining community groups, checking on your neighbors, or participating in mutual aid networks—you can maintain your cognitive flexibility even under stressful circumstances. As Solnit puts it, uncertainty can become a space of possibility rather than something to fear.)