Research has revealed a significant decline in the use of evidence-based language in American political speeches since the 1970s.
Findings published in the journal Natural human behavior stemmed from an analysis of over 8 million speeches delivered in the US Congress over the last 140 years.
“We wanted to understand why some politicians who frequently lie are perceived as honest,” stated Dr. Segun Aroyehun, the lead author of the study and a postdoctoral researcher at the University of Constance in Germany, as quoted in BBC Science Focus. “Often, it is because they speak about their beliefs and come across as genuine.”
Earlier research by Aroyehun and colleagues highlighted a shift in language usage among US Congress members towards belief-driven and intuitive language, departing from evidence-based language.
“There is a clear distinction between evidence-based truth and intuitive truth, where emotions play a crucial role,” Aroyehun explained.
To delve deeper, the team probed historical records to ascertain if this shift was a recent occurrence.
Utilizing machine learning models, the researchers combed through almost 150 years of Congress speeches, establishing a scoring system based on keywords signifying evidence-based or intuition-based language.
While evidence-based keywords comprised terms like “analysis”, “data”, “study results”, and “study”, intuition-based language included phrases such as “perspective”, “common sense”, “prediction”, and “believe”.
Each speech was assessed based on the evidence-intuition language ratio.
The results were striking. While the ratio fluctuated over the 140-year period, evidence-based language predominated until the 1940s, 1950s, and 1960s before a shift took place. Since the 1970s, intuition-based language has gradually gained prominence.
Aroyehun noted that this trend applied to both Democratic and Republican politicians, with a recent uptick observed in evidence-based language among Democrats.
He underscored that the ratio does not determine the veracity of the speech content.
Nonetheless, these linguistic shifts have had repercussions. The team juxtaposed these changes with measures of legislative polarization and income inequality, observing a simultaneous decline in parliamentary productivity—measured by statute quantity and quality—over this period.
“The core message here is the significance of rhetoric,” Aroyehun emphasized. “The nature of truth pursuit reflected in US Congress language is integral to gauging social and political well-being.”
The team aims to employ similar methodologies to analyze speeches in Germany and Italy, tracking trends across diverse democracies.
About our experts
Segun Aroyehun is a postdoctoral researcher affiliated with the Social Data Science Group at the University of Constance. He holds a PhD from Centro derestigación Computación, IPN, focusing on devising robust strategies to combat offensive content on social media. His research has been featured in publications like Natural human behavior and Natural Communication.
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Source: www.sciencefocus.com
