The rise and fall of rationality in language

Abstract

The surge of post-truth political argumentation suggests that we are living in a special historical period when it comes to the balance between emotion and reasoning. To explore if this is indeed the case, we analyze language in millions of books covering the period from 1850 to 2019 represented in Google nGram data. We show that the use of words associated with rationality, such as “determine” and “conclusion,” rose systematically after 1850, while words related to human experience such as “feel” and “believe” declined. This pattern reversed over the past decades, paralleled by a shift from a collectivistic to an individualistic focus as reflected, among other things, by the ratio of singular to plural pronouns such as “I”/”we” and “he”/”they.” Interpreting this synchronous sea change in book language remains challenging. However, as we show, the nature of this reversal occurs in fiction as well as nonfiction. Moreover, the pattern of change in the ratio between sentiment and rationality flag words since 1850 also occurs in New York Times articles, suggesting that it is not an artifact of the book corpora we analyzed. Finally, we show that word trends in books parallel trends in corresponding Google search terms, supporting the idea that changes in book language do in part reflect changes in interest. All in all, our results suggest that over the past decades, there has been a marked shift in public interest from the collective to the individual, and from rationality toward emotion.

Using big data to track major shifts in human cognition

“…The primary corpus for Scheffer et al ( 1 ) is Google Books. The release of that corpus was a major event, but researchers in cultural analytics later uncovered a range of deficits ( 8 ).…”

“…Scheffer et al’s ( 1 ) exciting new work reports an historic rearrangement, occurring in the late 20th century, of the balance between reason and emotion. Its approach is part of a new trend in the psychological sciences that uses extremely large volumes of text to study basic patterns of human cognition.…”

“…To establish their claims, Scheffer et al ( 1 ) use principal component analysis to identify two major polarities of correlated vocabulary words in the Google Books corpus ( 6 ). The first polarity (PC1) tracks a shift from archaic to modern, in both material life (“iron” is archaic, “computer” is modern) and culture (“liberty” is archaic, “privacy” is modern).…”

“…Their main finding then has two pieces: a shift from the intuitive pole to the rational pole (the “rise” of rationality) and then back (the “fall”) ( 1 ). The rise has begun by the start of their data in 1850, and unfolds over the course of a century or more.…”

“…The raw effect sizes the authors report are extraordinarily large ( 1 ). At the peak in 1980, rationality words outnumbered intuition words, on average, three to one.…”