Supplementary material from "Conversational alignment as an individual difference"

Speakers in conversation reuse each other’s words, structures, meanings, sounds, and gestures. This phenomenon—known as conversational alignment—is regarded as a cornerstone of successful communication and has garnered attention from researchers studying individual differences. The concept of individual differences in alignment, however, lacks both a theoretical and empirical foundation. To test whether alignment exhibits the stability expected from a trait-like individual difference, we analyzed four corpora with repeated measures, comprising 1,375 adult–adult and parent–child conversations. Lexical, structural, and semantic alignment scores exhibited correlations of approximately .50 within conversations and .20–.25 across time, interlocutor, and conversational context, providing little evidence for trait-like stability. Stability was generally higher in less conversationally skilled populations and across similar contexts. Based on our results, we hypothesize that individual differences in alignment reflect a skill, not a trait, and outline challenges for developing better measures.