By Christian Jarrett

Talk of personality in politics is often dismissed as idle gossip, but politicians’ personalities inform their policy choices, shape their campaigning style and predict their chances of electoral success.

In fact, there has been much speculation that personality may be key to understanding perhaps the biggest electoral shock ever – Donald Trump’s triumph in the 2016 US Presidential election. Many commentators have highlighted Trump’s unusually brash, extraverted and narcissistic personality and proposed that it may partly explain his appeal among some voters. However, before now, there has been little systematic evidence to support this claim.

A new open-access paper in Presidential Studies Quarterly addressed this lack of evidence, surveying 875 international experts about the personality traits of 103 political leaders, including Trump and 20 other populists, who took part in 47 elections in 40 countries around the world between 2015 and 2016. Alessandro Nai and his colleagues found that Trump’s traits were rated at the extremes even in comparison to other populist leaders, suggesting a “truly unique and off-the-charts public persona”.

The participating experts, who had a slight left-leaning political bias, had academic backgrounds in “electoral politics, political communication (including political journalism), and/ or electoral behaviour”. They each evaluated one political candidate using an established Big Five personality questionnaire and a shortened version of a Dark Triad questionnaire to tap less savoury traits (such that each politician was rated by multiple experts – Trump, for instance, was rated by 75 experts). The experts also scored the candidates’ campaigning style.

Nai’s team were careful to explain that “we do not claim to measure the candidates’ actual psychological profile – and even less, the clinical components of their psyche – but rather their perceived personality (reputation).”

According to the judgment of the participating experts, Trump’s personality is extremely extraverted; extremely low on agreeableness; extremely low on conscientiousness; extremely neurotic (i.e. low emotional stability); and also extremely high on narcissism, psychopathy and Machiavellianism. The only trait where he was rated as average was openness.

Even when compared against other populist leaders, Trump came out as having the lowest scores of all on agreeableness, conscientiousness and emotional stability, and the highest scores for narcissism and Machiavellianism. On extraversion he was only outscored by Vladimir Zhironovsky of Russia, and on trait psychopathy only by Arlene Foster of Northern Ireland and Nikola Gruevski of Macedonia. Trump scored significantly higher on all the Dark Triad traits when compared against the average scores of the other populist leaders, making him in the researchers’ words, “an outlier among the outliers”. And when comparing his profile against the average for non-populist leaders, the difference is “staggering”, they added.

In terms of campaigning style, Trump scored very high for the negative tone of his tactics and his use of appeals to voters’ fears, and he had the single highest score for use of character attacks. This fits with the general pattern in the data for traits like low agreeableness and low conscientiousness, and high Dark Triad scores, to correlate with negative campaigning styles.

Overall Nai’s team believe their data show that what is unique about Trump is not his lack of political experience (other world leaders, like Macron, share this background) nor his personal wealth (again there are other examples, like Putin and Berlusconi), but his personality style. “Systematic comparison between Trump’s public persona and the profiles of other mainstream and populist candidates shows that Trump is, indeed, off the charts.”

While this new study provides fairly comprehensive comparative data on Trump’s personality and that of many other global politicians, and also demonstrates that there are meaningful associations between politicians’ personalities and their campaigning styles, what it doesn’t do is provide causal evidence that Trump’s personality was the reason for his electoral success, nor for his subsequent behaviour in office.

Nai’s team do allow themselves to speculate about the future, however. They point out that given previous research on US presidents’ and other politicians’ personalities – suggesting, among other things, that strong extraverts tend to be more successful, narcissists are willing to take more risks, and disagreeable leaders pass more legislation successfully – that they would “advocate for caution when assuming that Trump will necessarily be a president without major achievements at the end of his term(s)”.

On the negative side, past research suggests narcissistic leaders tend to allow more unethical behaviour among their subordinates, and note that Trump scored very low on conscientiousness, a trait previously associated with success among former presidents.

“Overall,” the researchers concluded, “the comparison of [Trump’s] profile with trends in the literature suggests that Trump will continue to be in campaign mode and be relatively successful in (short-term) crisis management, agenda setting, and the setup of new legislative initiatives. At the same time, his profile will undoubtedly drive impulsive decisions … ” They added, “our results could support the prediction that Trump will be a chaotic president.”

—Donald Trump, Populism, and the Age of Extremes: Comparing the Personality Traits and Campaigning Styles of Trump and Other Leaders Worldwide

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest