The structure and history of English words that describe people.

The English language is filled with words that are used to describe people, such as "nice," "skilled," "conservative," and "attractive." This broad trait space includes words that describe personality but also words that describe people's physical, sociodemographic, and ideological differences. Here we define trait space as the sum of stable, comparative, and socially meaningful descriptors and map this space by combining large language models, human ratings, and historical text analyses. Across four studies, we (a) introduce a comprehensive trait list (2,847 trait words); (b) establish normative human ratings of these words (3,070 English speakers) along 24 dimensions drawn from prior literature; (c) identify a four-factor structure of fitness, agency, communion, and traditionalism from these dimensions, which covers 95.4% of trait words; and (d) reveal systematic differences in the coherence, valence, and evolution of these factors. Specifically, these four factors differ in their coherence (e.g., communion is the most semantically coherent while traditionalism the least), valence (e.g., communion and agency show more alignment between their semantic direction and valence than traditionalism and fitness; communion has more negative words while agency and traditionalism more positive ones), and historical usage (e.g., fitness and communion are older than traditionalism; communion is converging in semantic space while agency diverging). These findings showcase new large language model-based methods for discovering and analyzing trait words. We close by motivating a functional constructionist view: The meaning, structure, and use of traits constitute a culturally constructed toolkit that represents socially relevant individual differences to help navigate recurring interaction problems. (PsycInfo Database Record (c) 2026 APA, all rights reserved).