Personality, Role, and Expressive Style in Large Language Models: An Interactionist Analysis
This study addresses the limitations of current approaches that rely solely on prompting to specify Big Five personality traits, which often fail to ensure consistent personality expression in language model dialogues. Adopting an interactionist perspective, this work systematically demonstrates for the first time that personality expression emerges from the context-dependent interplay among personality settings, social roles, and expressive styles—challenging the conventional assumption that personality can be controlled through prompts alone. Through a factorial design generating English–Japanese dialogue data, combined with LLM-as-a-judge evaluation and cross-lingual comparative analysis, the study reveals that social roles significantly influence openness, expressive style predominantly shapes conscientiousness and agreeableness, and neuroticism is primarily driven by explicit personality settings. Notably, stable personality impressions can still be elicited through social roles and expressive styles even without explicit personality prompts, with highly consistent findings across both languages.