Dark personalities in politicians may intensify partisan hatred—particularly among their biggest fans

A new international study suggests that voters who support political candidates with darker personality traits—such as narcissism, psychopathy, and Machiavellianism—may experience stronger emotional divides from their political opponents. But this association appears only among those who feel a close ideological connection with these candidates, and not in response to disliked political rivals. The findings shed light on how the personality traits of leaders might influence public opinion, offering a deeper understanding of how political divisions are fueled not just by policies or party lines, but by the personal qualities of those at the top.

The study was published in the European Journal of Political Research by a team of researchers from the University of Amsterdam, the University of Lausanne, and Vrije Universiteit Amsterdam. They investigated how the so-called “dark triad” of personality traits might be linked to a growing emotional gap between political partisans, also known as affective polarization.

The dark triad refers to a group of three personality traits that are socially aversive but not necessarily pathological. These traits are narcissism (characterized by self-importance, entitlement, and a need for admiration), psychopathy (marked by emotional coldness, impulsivity, and a lack of empathy), and Machiavellianism (associated with manipulation, deceit, and a strategic focus on self-interest). While each trait is distinct, they often overlap and are linked to aggressive, exploitative, or unethical behavior—especially in social or leadership contexts.

Affective polarization refers to the tendency for people to feel emotionally connected to their own political party while harboring increasing dislike toward rival parties. This divide can reduce people’s willingness to cooperate across political lines, lower support for democratic values, and strain personal relationships. Recent years have seen a rise in political leaders with combative and self-centered personas, which prompted the researchers to ask: could the personality traits of political elites be contributing to the public’s deepening political animosity?

“I have been working on the dark side of personality and its importance in politics for a few years now. Jürgen Maier, one of my main collaborators, and I recently wrote a book titled Dark Politics, which presents an in-depth investigation into the role of dark traits in politicians—what they are, where they come from, and what their consequences can be,” said study author Alessandro Nai, an associate professor of political communication at the University of Amsterdam.

“The last chapter on that book hints at some nefarious democratic consequences of electing dark politicians, including in terms of democratic backsliding, poor handling of the COVID pandemic, and increased dislike for the out-party. This latter is of particular relevance, as it implied that electing dark leaders could be associated with fostering affective polarization in the public. This is what I then decided to explore further.”

To explore this, the research team brought together data from two major sources. The first was an expert survey known as NEGex, which asked political scientists to assess the personalities of leading candidates in 40 national elections held between 2016 and 2021. This included more than 90 high-profile figures such as Donald Trump, Angela Merkel, Jair Bolsonaro, and Emmanuel Macron. Experts rated these candidates on dark personality traits using a modified version of the “Dirty Dozen” scale, which includes statements like “tends to be callous or insensitive” and “wants to be admired by others.”

The second data source came from the Comparative Study of Electoral Systems, a collection of post-election surveys from around the world. These surveys measured the public’s emotional reactions to political leaders using so-called “feeling thermometers,” which ask people to rate how warmly or coldly they feel toward each leader. This allowed researchers to calculate the emotional distance between a voter’s preferred candidate and other candidates—an estimate of how polarized that voter felt.

By combining the two datasets, the researchers created a profile that matched roughly 34,000 voters with the dark personality traits of both their preferred and most disliked political candidates. They also factored in how ideologically close voters felt to these candidates, along with a range of demographic and political variables to account for other possible influences.

The results revealed a clear pattern. The dark personality traits of a voter’s preferred candidate were linked to stronger affective polarization—but only when the voter felt ideologically close to the candidate. In other words, voters who felt aligned with a narcissistic or manipulative political leader were more likely to show stronger emotional rejection of rival candidates. This association was not found for leaders who were ideologically distant or for those in opposing parties.

The effect was especially pronounced for one trait in particular: Machiavellianism. While narcissism and psychopathy also showed similar patterns, it was the tendency to manipulate and deceive—hallmarks of Machiavellianism—that showed the strongest link to increased affective polarization among supporters.

“In politics, we tend to follow what our leaders – that is, the most important political figures that lead the party we feel the most closely associated to – say and do,” Nai told PsyPost. “This is why we elect them in the first place, because we feel that they, somehow, reflect who we are and what we like. Our research shows that this affective attachment to our leaders is one of the causes of the affective polarization in the public, that is, the fact that voters increasingly actively dislike their political opponents, on top of disagreeing with them.”

“What we find is a relatively clear association between the personality traits of in-party leaders and the levels of affective polarization of their voters. Specifically, in-party leaders with a darker personality profile, in particular, Machiavellianism, are associated with increased affective polarization in their voters. This association is only correlational, of course, but it does suggest that electing dark leaders could, possibly, make the public as a whole more politically radicalized.”

Interestingly, the personality traits of disliked candidates did not show the same kind of influence. Even when those candidates scored high on dark traits, they did not significantly increase affective polarization. This suggests that it is not how much voters dislike their opponents that drives polarization, but rather how strongly they support and identify with dominant, dark-spirited leaders from their own side.

To ensure the results weren’t biased by the experts’ own political views, the researchers conducted several additional analyses. They adjusted the personality ratings to account for expert ideology, controlled for expert demographics, and also considered whether candidates used negative or fear-based rhetoric during campaigns. The findings held up across these checks, suggesting the results were robust.

“The clarity of the result surprised us a bit,” Nai said. “And while it makes theoretically sense, the fact that we did not find any strong effect for the dark personality of out-party leaders (that is, the leader of the party we dislike the most) was a bit of a surprise.”

“What seems to be mattering, according to our results, is who your leader is, no matter who the leader of your opponents is. This could have implications for the way we think about current politics in the United States, for instance: the personality of Trump should not be what drives affective polarization in Democratic voters, according to our general trends.”

Still, the researchers caution against interpreting these findings as definitive proof that politicians’ personalities directly cause affective polarization. Because the data is observational, it’s possible that the relationship goes the other way—that more polarized voters may be drawn to darker leaders. Experimental or longitudinal studies would be needed to determine which comes first.

“We should not conclude that the dark personality of leaders drives affective polarization in their base — it is also likely that more affectively polarized voters are more likely to support leaders with dark traits,” Nai noted. “Actually, the two mechanisms likely co-exist in a dark and polarizing spiral, which is something that we are start considering as further study.”

There are also limits to how widely the findings can be applied. The study focused on top-level politicians such as party leaders and presidential candidates, leaving open the question of whether similar patterns exist among local or regional officials. Since people often have more personal contact with local politicians, these dynamics might be even more pronounced at lower levels of government.

The study, “Ripping the public apart? Politicians’ dark personality and affective polarization,” was authored by Alessandro Nai, Frederico Ferreira da Silva, Loes Aaldering, Katjana Gattermann, and Diego Garzia.