With the U.S. Presidential Elections looming around the corner, you don’t have to be American to find yourself following the campaigns, be it voluntarily or involuntarily.  You might have had a myriad of thoughts, ranging from “Haha, there’s no way he’s running for President!” to “Haha, there’s no way anyone would vote for him!” to “What are these people thinking?!” to a final, desperate plea: “Can neuroscience explain this?!”

“Are Group A’s and Group B’s brains wired differently?” may be the most clichéd of pop-science headlines, but are liberals’ and conservatives’ brains “wired” differently?

Maybe it’s just your personality.

Jonathan Haidt, author of The Righteous Mind, believes that political differences come down to deep-seated psychological differences.  In his 2008 TED Talk , “The moral roots of liberals and conservatives”, Haidt tests the audience’s political stereotypes. In his hypothetical scenario, two American tourists in Italy, “Adam” and “Bill”, stop in front of Michelangelo’s David. “Adam” admires the fine aesthetics of the human body, while “Bill” reacts to the nude form by blushing in embarrassment. Now, which of the two men is more likely to have voted for George Bush? (Remember, this was 2008.) “Bill”, of course.

Haidt claims that this particular stereotype corresponds to reality. Liberals rank higher than conservatives in the personality trait, “openness to experience”, which makes them crave novelty and variety, while those low on the trait seek familiarity and safety.  According to his research, liberals and conservatives have a different set of moral foundations (Graham, Haidt, & Nosek, 2009).  More recently, Hatemi and Verhulst (2015) generated doubt about the causal link between personality traits and political attitudes; their findings suggest that the two develop independently of each other.

This doesn’t really answer much. To many neuroscientists, personality psychology can be a strange and confusing field; adding politics to the mix just acts as a magnet for criticism. Exploring political ideology from the sole perspective of psychology might make for interesting reading, but also generates many a raised eyebrow (and many rolled eyes). Before drawing any solid conclusions, let’s engage in my favourite pastime- delving into the neurocognitive and neurophysiological underpinnings of psychological theories.  It’s way more fun than it sounds, I promise.

Disgust, threat, and other fun stuff.

“It’s disgusting!”

While the above statement may or may not be an actual quote by an actual U.S. presidential candidate, in response to his female opponent’s bathroom break during a debate, the link between disgust and political ideology has been greatly explored.

To explore the neurophysiological link between disgust and political orientation, researchers measured skin conductance responses, which indicate greater sympathetic nervous system activation due to arousal. They found that people with greater physiological responses to disgusting images, such as of a man stuffing his mouth with live worms, were more likely to identify as right-leaning (and to oppose gay marriage, pre-marital sex, abortion, etc.) than those with less physiological responses to the same images (Smith et al., 2011).

In a functional Magnetic Resonance Imaging (fMRI- a method used to measure brain activity) study, Ahn et al. (2014) used a machine-learning method to predict individuals’ political ideology from their brain response to a disgusting stimulus.  Subjects passively viewed images while lying in a scanner, after which they rated all the images as disgusting, pleasant or threatening. In response to the disgusting images, two different brain networks predicted which of the two political ideologies (conservative or liberal) they subscribed to.

These studies suggest that conservatives are more sensitive to disgust.  Whether neuroscience can be used as an excuse for anyone’s rude comments on female bodily functions is still debatable, but let’s not open that can of worms now.

How do both groups fare in the face of threat? Hibbing, Smith, & Alford (2014) argue that conservatives and liberals differ in their physiological and psychological responses to threat, with conservatives being more biased toward negative environmental features.  Similarly, conservatives are more likely to interpret ambiguous facial expressions as threatening (Vigil, 2010).

In line with this, Dodd et al. (2012) explored how people of differing political leanings react to pleasant and unpleasant stimuli.  Skin conductance responses revealed that conservatives react more strongly to aversive images (a man with a spider on his face, an open wound with maggots, etc), while liberals have greater responses to positive images (a happy child, a cute bunny, etc). They tested the subjects’ cognitive responses by studying their subtle eye movements. According to the eye-tracking results, conservatives tend to fixate faster and longer on unpleasant stimuli, while the opposite was true for liberals.

Hmm, if these findings are anything to go by, that explains why so many people actually think that building a giant wall is a good idea.

The political brain.

Political ideology lies on a spectrum and definitions vary across countries. Studying people’s brains by packaging them into two neat groups on the polar ends of the spectrum may not paint a full picture, but it sure does yield some interesting results.

In a well-known study published in Nature Neuroscience, researchers compared the neurocognitive process of conflict monitoring in liberalism vs. conservatism. Conflict monitoring refers to checking one’s habitual response, and modifying it to whichever response the situation demands. The anterior cingulate cortex (ACC) is the brain region responsible for this, among other “rational” functions like decision-making, reward anticipation and emotion-regulation. Conflict-related ACC activity was measured using electroencephalography (EEG), a technique which records brain electrical activity (caused by neuron firing) in response to a psychological event. As hypothesized, liberals performed better in the conflict-monitoring task, and showed greater ACC activity (Amodio, Jost, Master, & Yee, 2007).

While the above study investigated the link between political attitudes and brain function, Kanai, Feilden, Firth, & Rees (2011) focused on brain structure.

Before going over the findings, let’s mull over this pressing question of utmost scientific importance – is the author COLIN FIRTH credited in this study, the same as Oscar-winning English actor COLIN FIRTH? According to my diligent research (I googled “colin firth neuroscience”), the answer is yes, that is him.

The Kanai study used structural MRI to calculate the gray matter volume of the ACC and the amygdala of subjects who self-reported their political leanings on a 5-point scale from “very liberal” to “very conservative”. While the ACC is involved in conflict-detection, the amygdala plays a role in fear-processing (among other affective functions). They found the ACC gray matter volume to be significantly larger in liberalism. On the other hand, increased right amygdala volume was seen in conservatism.

Building upon these results, Schreiber et al. (2013) studied which brain regions are activated during risk-taking behaviour. In this fMRI study, subjects performed a risk-taking decision-making task. Although conservatives and liberals did not differ much in their task performance, they did in their brain activity. Conservatives showed greater activity in the right amygdala, while liberals did in the left insula. The insula is involved in pain, consciousness, self-awareness and other emotional, social, and cognitive functions. The results suggest that liberals and conservatives process risk differently.

So, what can we conclude from these studies? Liberals have a more active anterior cingulate cortex, hence are better at conflict-monitoring, hence are more “rational”? Conservatives have a more active (right) amygdala, hence are more “emotional”?

No, it’s not that simple.  Those conclusions might make you feel superior about your political orientation, but be warned- just considering those reverse inferences might provoke audible groans from the global neuroscience community.  But more on The Dreaded Reverse Inference Plague later.

Time for the tin-foil hats?

Your physiology and political leanings are related, your brain anatomy and function is linked to your political belief… what’s next? Government-mandated fMRI sessions? Is reality turning into a dystopian sci-fi movie?

Haha! No, that’s ridiculous. It’s not like neuroscientists can alter political belief by brain stimulation- oh, wait.

In a recent study, Chawke & Kanai (2016) used transcranial Random Noise Stimulation (tRNS- a tool used for non-invasive brain stimulation) to stimulate the dorsolateral prefrontal cortex (DLPFC- a region involved in decision-making, conflict-detection, and error-feedback-processing), during political information-processing. During the experiment, participants were divided into groups and made to view conservative and liberal political campaign videos (David Cameron’s Conservative vs. Ed Milliband’s Labour Party).  The authors hypothesized that stimulating the DLPFC would alter subjects’ beliefs, when exposed to political information consistent with their own ideologies. That is, a person who identifies as liberal would reject their initial ideology in favour of a more conservative view, and vice versa. The results, however, were unexpected- subjects, irrespective of their initial political ideology and the campaign video viewed, showed a significant increase in conservative values.

I won’t judge you for- in a fit of uncharacterized irrationality- reaching for the aluminum foil and engaging in a quick DIY project. But before creating that conspiracy theory website and sending out that mass email to your loved ones, warning them to “WAKE UP, SHEEPLE!! Mind control technology is here!!”,  it’s useful to know that, like all neurocognitive methods, brain stimulation has its limitations.

Conclusions- what’s right and what’s left?

Politics and neuroscience- a potent combination that makes for fascinating research (and ample clickbait). While bickering over politics with that annoying acquaintance on social media, you might be tempted to cherry-pick your winning argument from that over-hyped study – “Right-wingers are nut jobs! It’s SCIENCE!!” But remember to take everything you read with a pinch of salt- it’s common for popular science websites to gloss over the scientific details and to draw far-fetched conclusions from weak data.

A problem plaguing functional neuroimaging research is the over-reliance on reverse inferences, or reasoning backwards by linking the observed brain activity to a particular cognitive process, without directly testing it (Poldrack, 2006).  An example of a problematic reverse inference would be: “Group A’s brain scans show more active amygdalae. Since this region is involved in emotional learning, Group A is more emotional than Group B”. If fMRI scans show greater amygdala activation, the only concrete conclusion is just that- that a particular group, in a particular experimental setting, showed greater amygdala activation.

So far, ‘neuropolitics’ research seems to be complicated by methodological limitations, dependence on self-reports and hastily-implied causal inferences (Correlation does not imply causation. Rinse. Repeat.). Most studies skirt around the exact definitions of “conservative” and “liberal”; in some papers, “conservative” and “rightist”, and “liberal” and “leftist” are used interchangeably. Another point to remember is that most of the studies discussed here have been from a U.S. American perspective (i.e. Republicans vs. Democrats).

From a social neuroscience perspective, there’s no denying that political neuroscience could bring great benefits. The possibilities for future research are several: Does your brain structure and function decide your political view, or vice versa? What happens in the brain when someone changes their political orientation? How does racial prejudice come into play during political decision-making? There is also need for more cross-cultural studies. With the European refugee crisis in full swing, rising xenophobia and increasing polarization of the political landscape, any neuroscience research that sheds light on what appears to be a dark and baffling time for the world, is research worth pursuing.

While there are plenty of enthusiasts, like John Jost of N.Y.U, who goes so far as to call political neuroscience “the beginning of a beautiful friendship” (Jost et al., 2014), the skeptics are not far behind. In his critical piece for E-International Relations, with the deliciously cynical title, “Neuroscience and Politics: Do Not Hold Your Breath”, Jan Slaby laments that neuroscientific tools are being misused by psychologists and political scientists to fit their narrative.

Before deciding whether you want to build a wall or a bridge between politics and neuroscience, remember to read with an open mind, but question when necessary – after all, that’s the way to make neuroscience great(er).