Can neuroscience provide evidence for a liberal and conservative thinking style?

It may seem like a stretch to say that one could predict whether you lean left or right by looking at a brain scan — no questions asked, no opinions voiced — purely based on your neuroanatomy. However, this might not be too far from reality — at least insofar as predicting thinking style, which has been shown to be somewhat distinct based on party association.

Does brain structure determine your beliefs, or do your beliefs change your brain structure? What about those who switch parties at some point? How do they fit in to this model? We’ll be discussing all of this. It’s a complicated issue with lots of variables in play, so we’re going to take a pretty deep look into this topic from all angles, so we can draw the most accurate conclusions.

Please keep in mind from the beginning that this is not an endorsement of any one political party. This is science — we’ll just be discussing the data. Ready?

Let’s begin…

Recent converging studies are showing that liberals tend to have a larger and/or more active anterior cingulate cortex, or ACC — useful in detecting and judging conflict and error — and conservatives are more likely to have an enlarged amygdala, where the development and storage of emotional memories takes place. More than one study has shown these same results, which is why I felt it was worth investigating.

A few questions to keep in mind: If these differences do legitimately exist, how can — or better yet — how should we use this knowledge? How can insight gained from research of this kind prove helpful in the quest for more effective communication across party lines? Can empathy and understanding of personality differences, without judgments or stereotyping, aid in the productivity of political debates around topics such as climate change or evolution?

A Few Clarifications

The idea of a genetic or a neurological difference between liberals and conservatives is a hot topic of debate. In fact, Chris has covered quite a bit of it on this blog. Consequently, there has been a lot of thorough criticism of these converging studies — the methods, types of subjects, error bars, the flaws in design, sample size, etc, etc, ad nauseam, ad infinitum. But more research keeps cropping up that shows this same trend, so I feel at this point we should be thinking a little more about what this all means in the big picture.

Maybe each study has some flaws — I can probably find a few things in every study that could be improved upon. I also know the danger of over-applying and over-generalization of results like these to an entire population, or assuming that a group tendency necessarily applies to every single person in that group. Correlations are also not the same as causation. So I get it. I don’t want MRI scans to become the phrenology of politics any more than you do.

But let’s not lose sight of the big picture here.

Like Chris had mentioned, some of these correlations between brain function/anatomy and specific political party are consistent across multiple studies, of varying design and methodology, over years of research. That tells me something. The exact analysis or interpretation of the individual studies might not be 100% correct as stated in those papers, but there is obviously a pattern, and that’s what I’m most interested in. In cases like these I tend to look more at the data and pay less attention to the analyses, drawing my own conclusions from the data across all the studies. One paper may not have all the answers, but I think there is enough mounting evidence in the stack of literature that we can start (carefully) drawing some conclusions.

The study-specific nitpicking has already been done — quite marvelously, I might add — so I won’t be doing that here. What I will do is look at the pattern across several of these papers and talk about what this implies in the larger scheme of things.

SCIENCE!!

Two neuro studies mentioned here on this blog recently, the Amodio study (Neurocognitive Correlates of Liberalism and Conservatism, 2007) and the Kanai/Colin Firth study (Political Orientations Are Correlated with Brain Structure in Young Adults, 2011), found similar results when comparing the neuroanatomy of liberals and conservatives. These are the ones I want to focus on.

The Amodio study found that liberalism correlated with greater activity in the anterior cingulate cortex, or the ACC, while the Kanai study found that liberalism correlated with increased gray matter volume or a larger ACC, as shown in MRI scans. Additionally, the Kanai study found that conservatism was correlated with increased volume of the right amygdala.

(P.S. Don’t be scared by the neuro-speak — I’ll explain it all, I promise)

From Kanai:

Recent work has shown a correlation between liberalism and conflict-related activity measured by event-related potentials originating in the anterior cingulate cortex. Here we show that this functional correlate of political attitudes has a counterpart in brain structure. In a large sample of young adults, we related self-reported political attitudes to gray matter volume using structural MRI. We found that greater liberalism was associated with increased gray matter volume in the anterior cingulate cortex, whereas greater conservatism was associated with increased volume of the right amygdala. These results were replicated in an independent sample of additional participants. Our findings extend previous observations that political attitudes reflect differences in self-regulatory conflict monitoring and recognition of emotional faces by showing that such attitudes are reflected in human brain structure. Although our data do not determine whether these regions play a causal role in the formation of political attitudes, they converge with previous work to suggest a possible link between brain structure and psychological mechanisms that mediate political attitudes.

Now, a first reaction might be: liberals have a larger ACC, and conservatives have a larger amygdala, therefore, we can tell someone’s political party by their brain structure! Brain scans at the polling booths!

Eh, not so fast. It’s more complicated than that. First, let’s define those brain areas.

What does the ACC do and why is it relevant?

The ACC has a variety of functions in the brain, including error detection, conflict monitoring1, and evaluating or weighing different competing choices. It’s also very important for both emotion regulation and cognitive control (often referred to as ‘executive functioning’) — controlling the level of emotional arousal or response to an emotional event (keeping it in check), as to allow your cognitive processes to work most effectively.

When there is a flow of ambiguous information, the ACC helps to discern whether the bits of info are relevant or not, and assigns them value. People with some forms of schizophrenia, Paranoid Type, for instance, typically have a poorly functioning ACC, so they have trouble discerning relevant patterns from irrelevant ones, giving equal weight to all of them. Someone can notice lots of bizarre patterns — that alone isn’t pathological — but you need to know which ones are meaningful. The ACC helps to decide which patterns are worth investigating and which ones are just noise. If your brain assigned relevance to every detectable pattern, it would be pretty problematic. We sometimes refer to this as having paranoid delusions. You need that weeding out process to think rationally.

Mental illness aside, being able to sort out relevant patterns from irrelevant patterns logically is difficult to do when heavy emotions are involved. Imagine being under extreme emotional duress (such as having a fight with your significant other) then sitting down to analyze a set of data, or read a story and pick out the main points. It’s ridiculously hard to think logically when you’re all ramped up emotionally. This is why emotion regulation goes hand-in-hand with cognitive control and error detection.

Too much emotion gets in the way of logical thinking, and disrupts cognitive processing. This is why in times of crisis, we learn to set aside our emotions in order to problem-solve our way out of a dangerous situation. Those with the ability to maintain low emotional arousal and have high cognitive control are generally better at handling conflict in the moment, plus tend to be the least permanently affected by trauma in the long term2. They tend to be more adaptable to changing situations (or have a higher tolerance for complexity), and have what we call cognitive flexibility.

So that’s the ACC. Now let’s look at the amygdala.

The Amygdala

The amygdala is part of the limbic system, the area of the brain associated with emotions. The amygdala is important for formation of emotional memories and learning, such as fear conditioning, as well as memory consolidation. Emotions significantly impact how we process events; when we encounter something and have a strong emotional reaction — either positive or negative — that memory is strengthened.

Persons with a larger or more active amygdala tend to have stronger emotional reactions to objects and events, and process information initially through that pathway. They would be more likely swayed towards a belief if it touched them on an emotional level.

Those with a larger amygdala are also thought to experience and express more empathy, perhaps explaining why one of the features of psychopathy is a smaller amygdala. This is not to say that someone with a smaller amygdala is a psychopath, just that they are probably less emotionally reactive or receptive.

On the other hand, while emotional sensitivity can be a good thing, too much emotionality can have negative consequences. For example, Borderline Personality Disorder, characterized by poor and uncontrollable emotion regulation, features a hyperactive amygdala.

How do these brain functions fit in with political affiliation?

The obvious question we should be asking first is: What does it mean to be liberal or conservative? As a nation, we have been through wars, major financial crises, human rights revolutions, and during each of these significant historical events, the core values or prominent issues backed by the liberal and conservative party seem to change somewhat. Because of this, it wouldn’t be accurate to say a liberal 50 years ago looks the same as a liberal today. So can we really say there is a liberal or conservative “thinking style” if the issues paramount to each party are always evolving? Actually, I think we can. Really, it isn’t so much the specific issue that defines the thinking style, it’s the preference for either stability or change. Depending on the current events, this can mean very different things.

There was a recent article in the Guardian titled, “What does it mean to be a liberal?” in which liberalism is described as adaptability to a changing environment. If you look at liberalism as adaptability, and conservativism as stability, the party reactions to various events such as gay marriage (liberals want acceptance and change to new ways of thinking, conservatives want stability of previously held values), war (liberals are willing to adapt to shifting world views, while conservatives see war as a means of “preserving the stability of the homeland”), or even the current financial crisis — all make perfect sense.

Now, think back to the neuro data.

Remember, the Kanai study found a correlation between increased volume of the right amygdala and the tendency to identify with the conservative party. A recent unrelated study of emotion regulation strategies and brain responses showed that there is specific lateralization of brain activation depending on the type of regulation strategy employed. Translation: Using reappraisal strategies — sometimes thought of as “intellectualizing” or cognitive reevaluation — activated the left side of the amygdala, while emotional suppression of visible behaviors and feelings activated the right side.

Remember, conservatives were found to have a larger right amygdala, the side activated when attempting to hide or suppress and emotional reaction, rather than using logic and reason to reassess a situation, which would activate the left side.

Let’s assume, for sake of discussion, that all of the data in these studies hold. What would that imply?

Past studies, as well as the ones mentioned here, have shown that liberals are more likely to respond to “informational complexity, ambiguity, and novelty”. Considering the role of the ACC in conflict monitoring, error detection, and pattern recognition/ evaluation, this would make perfect sense. Liberals, according to this model, would be likely to engage in more flexible thinking, working through alternate possibilities before committing to a choice. Even after committing, if alternate contradicting data comes along, they would be more likely to consider it. Sound familiar? This is how science works, and why there might be so many correlations between scientific beliefs (and lesser belief in religion) and tendency to be liberal. Is this a hard and fast rule? Of course not. But you can see the group differences overall.

Now let’s look at the other side. Conservatives, more likely to have an enlarged amygdala, would tend to process information initially using emotion. According to Kanai,

Conservatives respond to threatening situations with more aggression than do liberals and are more sensitive to threatening facial expressions. This heightened sensitivity to emotional faces suggests that individuals with conservative orientation might exhibit differences in brain structures associated with emotional processing such as the amygdala.

So, when faced with an ambiguous situation, conservatives would tend to process the information initially with a strong emotional response. This would make them less likely to lean towards change, and more likely to prefer stability. Stability means more predictability, which means more expected outcomes, and less of a trigger for anxiety.

Liberals, though, tend toward unpredictability. They don’t mind change, and in fact, they prefer it. They seek it out. This personality type would likely choose “change” over “stability” just because they tend to be more novelty-seeking by nature. The fact that they have a more prominent ACC helps them to deal with radically changing situations, still find the salient points, all without the emotion getting in the way. These individuals are the compartmentalizers, the logic-driven ones, while the conservatives are the ones driven by emotion and empathy.

What does this boil down to in practical terms?

In order for a person to embrace a cause or idea, it needs to be meaningful for them. Each type of person has a different way that they assign meaning and relevance to ideas. Let’s take liberals and conservatives, since we are theorizing that they are two distinct thinking styles: liberals would be more flexible and reliant on data, proof, and analytic reasoning, and conservatives are more inflexible (prefer stability), emotion-driven, and connect themselves intimately with their ideas, making those beliefs a crucial part of their identity (we see this in more high-empathy-expressing individuals). This fits in with the whole “family values” platform of the conservative party, and also why we see more religious folks that identify as conservatives, and more skeptics, agnostics, and atheists that are liberal. Religious people are more unshakable in their belief of a higher power, and non-religious people are more open to alternate explanations, i.e., don’t rely on faith alone.

So — for liberals to make a case for an idea or cause, they come armed with data, research studies, and experts. They are convinced of an idea if all the data checks out–basically they assign meaning and value to ideas that fit within the scientific method, because that’s their primary thinking style. Emotion doesn’t play as big of a role in validation. Not to say that liberals are unfeeling, but just more likely to set emotion aside when judging an idea initially, and factor it in later. Checks out scientifically = valuable. Liberals can get just as emotionally attached to an idea, but it’s usually not the primary trigger for acceptance of an idea.

Conservatives would be less likely to assign value primarily using the scientific method. Remember, their thinking style leads primarily with emotion. In order for them to find an idea valuable, it has to be meaningful for them personally. It needs to trigger empathy. Meaning, they need some kind of emotional attachment to it, such as family, or a group of individuals they are close to in some way.

A Reminder

This is not meant as a criticism or an endorsement for one style over the other, but merely pointing out that there are definite differences between groups in primary thinking or processing style. Also, this data was assumed to be correct for the sake of this hypothetical discussion. With that said, there are some very important things to take into account before drawing any final conclusions. If you skip this last part, you’re missing half the point of this entire analysis, so keep reading. Also, I’ll be really sad if you give up now, and no one wants that.

This is wicked important!!

We can’t have this conversation without considering the following things about neuroscience and psychology as they relate to politics:

1. The brain is plastic.

Meaning, every time we engage in any activity, our brain changes somewhat, even if only to a very small degree. In fact, your brain is a little bit different right now than when you started reading this article. And a little different now. Engaging in any activity excessively or intensely over a long period of time changes your brain even more—such as training for a sport or spending a long time practicing and becoming proficient at a skill. Conversely, if you stop using an area of your brain to a significant degree, it will probably shrink in size due to lack of connectivity, similar to the atrophy of muscles.

When it comes to the brain areas measured in these studies, we aren’t sure how much of the difference was there to begin with, or to what degree the brain changed as a function of being in a particular political party. I suspect both things contribute somewhat. How much? We have no way of knowing at this point. To say conclusively, we need a longitudinal study, with control groups, measuring brain volume before and after joining, leaving, or participating in a political party’s activities or ideologies.

2. Not everyone fits into little personality boxes.

The world just loves the idea of personality defined by linear spectrums of traits that are the opposite of one another. I’m guilty of this myself at times. We assume everyone occupies one data point on that spectrum, neatly dividing people into categories based on how close they are to one or the other end: thinking vs feeling, introvert vs extrovert, and so on. This may be true for some people, but not everyone.

You are probably familiar with the Myers-Briggs personality inventory, where they define you as ‘types’ based on your standing on four separate dichotomies, giving you a profile of INFP, ESTJ, and so on. One of these dichotomies is the thinking/feeling, or logical/emotional scale. People naturally assume that since these are opposite types of processing styles, that one would lean toward one or the other, thus defining themselves as either a ‘rational’ or an ‘intuitive’ thinker. Well, some people can actually be extreme on both ends, as explained by Scott Barry Kaufman in his recent article on the ‘Renaissance’ thinking style. Personally, depending on what kind of mood I’m in or when I take the test, I could get a different result every day.

Just because someone rates high on emotionality, that doesn’t mean they automatically rate low on rationality, and vise versa. Some people are clearly more on one end of the spectrum than the other, but some people are weighted relatively equally on both ends of the spectrum — not in the middle of the two, but extreme on both ends — they are able to go back and forth between thinking styles depending on the situation. This is very important to keep in mind when you talk about labeling and sorting people into categories based on one measure of a trait.

3. Political affiliation is a choice.

One of my pet peeves is hearing people talk about “the conservative gene” or the “liberal gene”. That’s like saying there’s a “rollercoaster affinity gene” or a “Mint-Chocolate Chip Ice Cream Gene” (If that exists, I have it) (yes, I’m kidding).

True, certain personality traits, which are heritable, tend to influence dominant thinking, feeling, or processing styles; those personality traits influence behaviors and preferences. A personality type that is defined as “thrill-seeking” is probably more likely to enjoy rollercoasters than a personality type that is anxious in large crowds. But a thrill-seeker doesn’t necessarily love rollercoasters, for any number of reasons.

A person chooses to join a political party; they are not forced into one straight from the womb. The tendency for a personality type to be likely to engage in a set of somewhat related behaviors is not a genetic cause for a behavior. There is a lot of variability, even with genetic predisposition. Also, there is very rarely one gene that accounts for anything, especially when we are talking about conditions of complex traits like personality style or psychological disorders.

4. People tend to join networks of peers that are like themselves, regardless of specific political issues.

The majority of the population is not terribly well-informed about the current political issues. Yes, a portion of the population is extremely involved and loyal to their party’s mission — but most people are pretty apathetic, and will just go along with what their peers are doing. Sad, but true. When that happens, the party as a whole tends to take on the personality of the dominant leaders at that point in history, and attract people who respond to that type of personality or communication style.

So on some level, I see political parties being a bit like personality clubs, with only a portion that really knows what’s going on in politics or utilizing their decision-making power. If you’re reading this article right now, you are likely in that informed and decision-making portion, but not everyone that identifies with your party is. Studies like the ones mentioned don’t give quizzes to see if the participants are politically savvy or even if they know who the president is; they just ask which party they identify with. That’s a pretty significant point right there.

Conclusions and Discussion

When we speak of “liberal and conservative thinking styles” the most important thing to keep in mind: we are talking about group differences, not individual differences. The people that fit into this two-category model described here are generally the most active and hard core members of the parties. This doesn’t account for moderates, nor does it take into account extreme fanatics of both wings, where we start to see mental instability confounding the group traits. Both sides have a little extremity and their fair share of imbalanced individuals in the fringes, so don’t assume any one party is immune.

Additionally, this “liberal/conservative thinking style” division doesn’t account for those types of individuals mentioned up there in point number 2. Some people are just really complex. Maybe they are highly emotionally sensitive and have a large amygdala, but also have a prominent ACC and prefer novelty and ambiguity. Those people exist, and I know some of them personally. The really complex people never fit neatly into models like these. Furthermore, I hypothesize that those complex people are more likely to be the ones to switch parties at some point. Because they have the traits that make them receptive to both kinds of arguments — logical and emotional — it might take one particular issue that strikes a chord that swings them one way or another. However, I don’t think these “party switchers” are necessarily moderates; they may be just as extremely committed to those new ideals as they were the old ones. Also, these “party-switchers” might be the best ones to champion reaching across party lines; they know, to some extent, how the other side feels and how best to reach them. I would love to see further research on this cohort in particular.

Finally, how can this information be used for good (and not evil)?

Well, it’s clear that there are group differences in party thinking style. When a party is trying to rally its base and speak to their own, they will use those communication styles that work for them, which makes perfect sense. Liberals will rally with data and strong, logical arguments, and conservatives will hammer away about family values and stability. This works really well for strengthening your in-group. But it doesn’t do any good trying to cross party lines with those same tactics, because the other side just isn’t as receptive to those arguments and communication styles as you are.

So you know what this means? Yep — each side is going to have to recognize that not everyone thinks like them, processes information like them, or values the same types of things. Each party is going to have to think of, i) what idea they are trying to communicate, ii) how that other group responds best to presentation of information (what turns them on or off), and iii) how to present it to that other group in a way that is both meaningful and non-threatening.

Yes, I know that’s asking a lot, but tough times call for tough measures. We have some scientific data here. It may not be perfect, but it’s a good start. With the state our country is in right now, I don’t think we have any choice but to cowboy up and do whatever needs to be done in order to reach some common ground. Not just one party bending, but both parties — and it needs to happen soon.

This is an invited guest post by Andrea Kuszewski, a Behavior Therapist and Consultant for children on the autism spectrum based in Florida, and a researcher and manager with VORTEX: Integrative Science Improving Societies, based in Bogotá, Colombia. She blogs at The Rogue Neuron and tweets as @AndreaKuszewski.

1. For a great discussion and explanation of conflict monitoring as it relates to cognitive control, check out this paper [PDF] by Botvinick, Carter, Braver, Barch, and Cohen.

2. That’s a general tendency, but there are individual exceptions.

PRIMARY REFERENCES

David M. Amodio et al, Neurocognitive Correlates of Liberalism and Conservatism, Nature Neuroscience, Vol. 10, No. 10, October 2007.

Ryota Kanai et al, Political Orientations Are Correlated with Brain Structure in Young Adults, Current Biology, 21, 1-4, April 26, 2011.

Additional Reading

Matthew M. Botvinick, Jonathan D. Cohen and Cameron S. Carter, Conflict Monitoring and Anterior Cingulate Cortex: An Update, Trends in Cognitive Sciences, Volume 8, Issue 12, 539-546, 1 December 2004.

Botvinick MM, Braver TS, Barch DM, Carter CS, Cohen JD, Conflict monitoring and cognitive control. Psychol Rev. 2001 Jul;108(3):624-52.

Arne Dietrich and Michel Audiffren, The reticular-activating hypofrontality (RAH) model of acute exercise, Neuroscience & Biobehavioral Reviews, Volume 35, Issue 6, May 2011, Pages 1305-1325.

Donegan et al.; Sanislow, CA; Blumberg, HP; Fulbright, RK; Lacadie, C; Skudlarski, P; Gore, JC; Olson, IR et al. (2003). “Amygdala hyperreactivity in borderline personality disorder: implications for emotional dysregulation“. Biological Psychiatry 54 (11): 1284–1293.

Kerns JG, Cohen JD, MacDonald AW 3rd, Cho RY, Stenger VA, Carter CS, Anterior cingulate conflict monitoring and adjustments in control. Science, 2004 Feb 13;303(5660):1023-6.

Krusemark, E. & Li, W. (2011). Do all threats work the same way? Divergent effects of fear and disgust on sensory perception and attention. Journal of Neuroscience, 31(9), 3429-34.