Psychology often revolves around understanding correlations—how we can link these to causation. We often hear the phrase, “correlation does not imply causation,” particularly in data analysis. A well-known example is the correlation between ice cream sales and crime rates. While ice cream doesn’t drive criminal behavior, the summer months likely influence both factors.
Yet, this isn’t a rigid rule. Correlation can sometimes hint at causation. Psychologists deal with this regularly. For instance, there’s been a long-standing observation that people who sleep less typically struggle with memory, attention, and decision-making tasks. Also, younger individuals with unpredictable bedtimes often have poorer academic performance. This is another case of correlation—until recently, neuroimaging technology has provided evidence to establish causation.
This week’s Mini Philosophy interview featured award-winning author Leor Zmigrod, who discussed her new book, The Ideological Brain. In it, Zmigrod examines extreme ideologies, including the correlations found in her research. During our talk, she identified four major factors associated with extreme ideological beliefs.
In essence, these factors can often lead individuals to become extremists.
Cognitive rigidity
“Cognitive rigidity refers to viewing the world in a binary way,” Zmigrod explains. “People with this trait find it challenging to adapt and tend to think along a single path without considering alternative perspectives.”
There are various tests for this rigidity. Zmigrod prefers asking individuals to think of potential uses for an item. For example, if I showed you a Coca-Cola bottle, what could it be used for?
A rigid thinker might only see it as a container for liquid, while others might suggest it could serve as a candle holder, terrarium, vase, or even a salt shaker. This rigidity is often linked to extreme ideologies. Research indicates that increased cognitive rigidity is associated with a higher likelihood of extremism.
Emotional volatility
The second factor is “emotional impulsivity,” which means being prone to thrill-seeking and sensation-seeking behaviors in everyday life. Zmigrod portrays these individuals as those rushing to the front of any line.
This isn’t too surprising. It seems logical that people who lead extreme lives might gravitate towards extreme ideologies. However, this personality trait comes with other tendencies, such as an inclination towards violence and self-sacrifice.
Think about your friends: Who’s most likely to start a fight? Who tends to act impulsively? It’s worth considering how extreme their beliefs might be.
Amygdala
The next two indicators of extremism lie within our brains—specifically, they’re not readily visible. In the interview, Zmigrod pointed out two neurobiological factors linked to a higher possibility of extremism, starting with the amygdala.
“The amygdala processes negative emotions like fear and disgust, and studies show it tends to be larger in individuals with right-wing beliefs compared to those with left-wing beliefs. This finding has been consistent across various countries and large participant groups, indicating a possible predisposition toward either ideology,” Zmigrod notes.
There’s substantial research available for us, and it’s up to the audience to make the connections they see.
Prefrontal cortex
The other neurological aspect tied to extreme ideologies relates to decision-making capabilities found in the prefrontal cortex. A 2025 study highlighted that individuals with a thinner “dorsomedial PFC cortex” often displayed stronger authoritarian traits in both left- and right-wing contexts, after adjusting for variables like age and total brain size.
As Zmigrod summarizes, “The brain exhibits different functions and structures based on beliefs in fundamentalism versus moderation.”
These observations remain primarily correlative. Proving causation, like we have with sleep studies, may require further exploration and technology. Yet, the answers are likely to be complex.
Working backward
The process of belief formation is intricate, drawing insights from neuroscientists, psychologists, and philosophers alike. It’s unlikely we can pinpoint one single cause for extreme views. Various backgrounds—nature versus nurture, biology versus environment—meld together in a complicated mixture.
What’s particularly intriguing is how we can react to these observations, especially the first two factors. If cognitive rigidity and emotional volatility are linked to extremism, perhaps we could intervene. By nurturing emotional stability and encouraging flexible thinking, we might counter the rise of extremism. When discussions become shouting matches in polarized groups, the results are rarely positive. Maybe we can turn the tide if we just think creatively—like coming up with more than one use for a Coke bottle.
