New research from Europe has found that culturally liberal politicians use more complex language than their socially conservative counterparts. The findings have been published in the open-access scientific journal PLOS One.

“Many have ridiculed Donald Trump for his use of simple language with low levels of linguistic complexity. The Washington Post, for instance, reported that Trump “speaks like a 5th grader” (here), while other politicians used language as complex as that of 6th-8th grader,” said study author Bert N. Bakker (@bnbakker) of the University of Amsterdam.

“Beyond its headline-grabbing appeal, this finding speaks to the more general claim in political science (and psychology) that conservative politicians use simpler, less complex language than liberals. See for instance the intriguing work by Philip Tetlock (1983 and 1984) and John Jost (2016) on the topic.”

“We were wondering how their findings that liberals and conservatives differ in their language complexity would translate into the European party system where parties don’t only differ on more than one ideological dimension,” Bakker said.

The researchers used the Flesch-Kincaid readability test, which is based on average sentence length and average number of syllables per word, to analyze political speeches from European countries between 1946-2017. They found that culturally liberal politicians tended to use more complex language in their speeches. But the researchers found no association between economic ideology and the complexity of politicians’ language use.

“We find that speakers from culturally liberal parties use more complex language than speakers from culturally conservative parties. We find this evidence by analyzing 381,609 speeches given by politicians from five parliaments, by twelve European prime ministers, as well as speeches from party congresses over time and across countries (United Kingdom, Germany, Spain, the Netherlands and Sweden). Our findings give clear descriptive evidence for a link between social conservatism and language complexity,” Bakker told PsyPost.

“What is striking is that we came across the same results across different countries, different speeches and different types of politicians,” said co-author Martijn Schoonvelde. “For instance, our scores show that former culturally liberal British Prime Minister Gordon Brown delivered speeches that were markedly more complex than his successor, the culturally conservative David Cameron.”

“We saw the same thing in Spain, where the language used by liberal Prime Minister José Zapatero was much more complex than that of his successor, the conservative Mariano Rajoy,” Schoonvelde explained. “There are also notable differences between countries. For example, the culturally liberal German politician Joschka Fischer and British liberal Nick Clegg score much higher for the complexity of their language use than the conservative Dutch politician Geert Wilders or his Swedish counterpart Jimmie Åkesson.”

However, it is still unclear why the difference in language complexity exists.

“This study opens up for new avenues of research. First, it would be interesting to study the differences in language complexity by politicians of the same political party. Second, future work could theorize and test why politicians differ in their language complexity. Do they do this out of strategic reasons, such as maximizing votes? Or do they do this because their language use actually reflects differences in the personality of these politicians,” Bakker said.

The study, “Liberals lecture, conservatives communicate: Analyzing complexity and ideology in 381,609 political speeches”, was authored by Martijn Schoonvelde, Anna Brosius, Gijs Schumacher, Bert N. Bakker.