Republican presidential candidate, businessman Donald Trump greets supporters after a campaign rally, Monday, Dec. 21, 2015, in Grand Rapids, Mich. (AP Photo/Carlos Osorio)

Being a Washington outsider almost seems to be necessary to succeed in the Republican primaries, where it seems that “the party faithful are keen to decapitate politicians with experience of politics,” as Lexington put it recently in The Economist.

American candidates aren’t the only ones who accuse the elite of being incompetent, corrupt and uninterested in ordinary people. This anti-establishment rhetoric is also used by such European political parties as the Austrian Freedom Party, the Danish People’s Party, the UK Independence Party, the National Front in France, Die Linke in Germany, Podemos in Spain, and many others (see here)—populists all.

For instance, recently, the Party for Freedom leader Geert Wilders proclaimed the Dutch parliament a “fake parliament” that “no longer represents ‘the people’.” And Germany’s Die Linke complains loudly that the “typical backroom politics” in Germany should end.

[How hostile are Trump supporters to Muslims? This new poll will tell you.]

These populist parties differ profoundly in ideology. But their voters share an important characteristic. In our recently published study in the European Journal of Political Research (here’s an open access version), we show that the common denominator of those who vote for these parties is not, as has often been claimed, their socioeconomic position. Rather, they are united by personality.

The personality of populism

There is a long tradition in political psychology that links political attitudes to personality (see for an overview Mondak & Halperin 2008). For example, according to the congruency model of political preferences voters appreciate politicians and parties similar to their own personality (Caprara & Zimbardo 2004 and Jost, Federico and Napier 2009). Accordingly, politicians can win over voters by adjusting their rhetoric to the personality of those voters.

[Donald Trump is a textbook example of an ideological moderate]

One common denominator of populist parties – also discussed here – is that populist parties share an anti-establishment rhetoric. This message portrays the ruling political elite as evil, working for their own gain, and uninterested in the common people.

So when is someone drawn to a populist party with an anti-establishment message? When that party and its leader are congruent with that person’s personality.

The Big Five personality traits

To evaluate this we use the Big Five personality framework which isolates five relatively stable personality traits: Openness, Conscientiousness, Extraversion, Agreeableness and Neuroticism (here’s an introduction). Scores on these traits are self-reports of how  participants generally describe themselves.  Scores on these traits correlate with congressional behavior, political ideology and voting behavior in, for instance, the U.K. and U.S.

We turn our attention to one of the Big Five traits, namely Agreeableness. The higher individuals score on Agreeableness, the more altruistic, trusting, cooperative and tender-minded they are. The lower individuals score on Agreeableness, the more egoistic, distrustful and uncooperative they are. In the political domain, people who score low on the “Agreeable” scale are more suspicious of politicians and feel that they have little political influence.

Please note that these personality characteristics are not value judgments. Someone can be overly trusting to the point of being naïve, and skepticism might be useful when it comes to politics.

[No, Donald Trump’s candidacy does not mean that politics are completely different now]

We propose that the populist anti-establishment message – accusing the political elite of incompetence, insubordination and profiteering at the expense of the common people – matches this distrusting, tough-minded and cynical personality.

Three countries with the same result

We assessed whether lower levels of Agreeableness are associated with support for the tea party in the U.S., the Party for Freedom in the Netherlands and Die Linke in Germany. These parties (or faction within a party, in the case of the tea party) differ in their ideology but share an anti-establishment message. Support for populist parties is measured with questions about support for the tea party in the U.S., with answers about whether individuals plan to vote for the Party for Freedom in the Netherlands, and with anyone who actually voted for Die Linke in Germany.

Personality was measured using short self-reported measures of personality, in which respondents indicate to what extent they agree with statements about themselves. In all studies we controlled for socioeconomic status, education, race, ideology. Moreover, we control for authoritarianism, a personality trait which captures the motivation to maintain conformity, uniformity and order.

As can be seen in the figure below, there is a negative association between Agreeableness and support for the tea party in the 2012 American National Election Studies. The graph shows how likely someone is to strongly support the tea party based on how highly they rank on Agreeableness. The lower the score on Agreeableness, the higher the likelihood that person will strongly support the tea party.


Agreeableness and support for the tea party

Turning to our samples in Europe, we see a similar pattern: Low-agreeable voters are more likely to support a populist party than high-agreeable voters. For instance, the figure below plots the probability of voting for the Dutch Freedom Party against an individual’s agreeableness score. As can be seen, low-agreeable voters are more likely to vote for the populist party than high-agreeable voters.

In Germany we report (see the top figure below) we report a similar finding. Again, the effects are modest but consistent.

Agreeableness and support for the Party for Freedom (above) and Die Linke (below)


Agreeableness and support for the Party for Freedom in The Netherlands

Agreeableness and support for Die Linke in Germany

Our study cannot explain the rise and fall of populist parties over time. Increased media attention is one option. As John Sides explained on this blog, increasing media attention for Trump coincides with increased support, while decreasing attention for Trump correlates with a drop in the polls. What’s more, our study reports correlations. We cannot test whether having a particular personality actually causes voting for populist parties.

[Can we stop blaming the media for Donald Trump? Nope. Not at all.]

Personality is destiny — or at least, politics

Populists like Donald Trump, Sarah Palin, Geert Wilders, Nigel Farage and Marine Le Pen claim to speak the language of the common people — unlike the ruling elites, who do not. Our study indeed suggests congruence between the populist message and the personality characteristics of those who vote for parties that express such a message.

This suggests that populists will, most likely, not be able to persuade agreeable voters. Therefore, the populist strategy has its limitations. For non-populist leaders it will be hard to win over low-agreeable voters, as long as they have to compete with populists.

Bert Bakker is assistant professor of political communication & journalism, Matthijs Rooduijn is a postdoctoral researcher at the Amsterdam Centre for Inequality Studies (AMCIS) and Gijs Schumacher is assistant professor of political science at the University of Amsterdam.