Twentieth century morality: The rise and fall of moral concepts from 1900 to 2007.

Trends in the cultural salience of morality across the 20th century in the Anglophone world, as reflected in changing use of moral language, were explored using the Google Books (English language) database. Relative frequencies of 304 moral terms, organized into six validated sets corresponding to general morality and the five moral domains proposed by moral foundations theory, were charted for the years 1900 to 2007. Each moral language set displayed unique, often nonlinear historical trajectories. Words conveying general morality (e.g., good, bad, moral, evil), and those representing Purity-based morality, implicating sanctity and contagion, declined steeply in frequency from 1900 to around 1980, when they rebounded sharply. Ingroup-based morality, emphasizing group loyalty, rose steadily over the 20th century. Harm-based morality, focused on suffering and care, rose sharply after 1980. Authority-based morality, which emphasizes respect for hierarchy and tradition, rose to a peak around the social convulsions of the late 1960s. There were no consistent tendencies for moral language to become more individualist or less grounded in concern for social order and cohesion. These differing time series suggest that the changing moral landscape of the 20th century can be divided into five distinct periods and illuminate the re-moralization and moral polarization of the last three decades.