Politicians who exhibit ‘dark’ personality traits such as narcissism, psychopathy or Machiavellianism contribute to increasing affective polarisation among citizens. This is the conclusion of a new study conducted by the University of Amsterdam (UvA), the University of Lausanne and Vrije Universiteit Amsterdam, recently published in the European Journal of Political Research.

The researchers linked the personality profiles of over 90 prominent politicians worldwide with voter attitudes in 40 national elections. The results reveal striking patterns. Politicians who score high on the so-called Dark Triad – narcissism (excessive self-focus), psychopathy (emotional coldness and lack of empathy), and Machiavellianism (a tendency toward manipulation and deception) – are associated with greater hostility toward political opponents among their followers.

Polarisation from within
The researchers show that dark traits have an effect when voters feel ideologically close to the politician in question. The stronger the identification, the more likely supporters are to adopt hostile stances. ‘Machiavellian politicians in particular – strategic, manipulative, goal-driven – appear to be catalysts for affective polarisation: they deepen emotional divides between their supporters and others,’ explains Alessandro Nai, researcher at the UvA.

Remarkably, the personality traits of political opponents have little to no effect on the degree of polarisation. Nai: ‘We know today that voters tend to take cues from politicians they feel close to, and are more likely to ignore messages from politicians they disagree with. It is thus our own politicians who make us angrier, fuel hostile thinking towards others, and contribute to affective polarisation. And this can have dramatic consequences.’

Dominant leaders
The study included leaders such as Donald Trump, Jair Bolsonaro, Emmanuel Macron, Marine Le Pen, Angela Merkel, Theresa May, Jeremy Corbyn, Boris Johnson, Viktor Orbán, Narendra Modi, Silvio Berlusconi, Shinzo Abe, Recep Tayyip Erdoğan and many others. Dutch politicians such as Mark Rutte and Geert Wilders were also part of the analysis. While no individual scores are disclosed, the researchers emphasise a broader trend: during times of political tension, voters tend to prefer dominant, hardline leaders, even when they exhibit norm-breaking or confrontational behaviour.

Democratic risks
The findings cast a critical light on the global rise of ‘dark’ leaders. According to the researchers, the confrontational and uncompromising personality traits of such leaders pose clear risks to democratic processes. ‘When the personal traits of leaders poison public discourse, the public’s willingness to cooperate weakens, social cohesion suffers, and ultimately democratic norms erode,’ says co-author Katjana Gattermann of the UvA.

The researchers call for greater awareness of the role (dark) personality plays in political leadership, in particular when these traits appear in strongmen. Nai concludes: ‘We have shown in previous research that dark personality traits are particularly frequent in authoritarian leaders and populists; the evidence seems thus to be piling up that narcissism, psychopathy, and Machiavellianism are important phenomena if we want to understand why politics, today, seems so confrontational.’