LLM Psychological Profiles Are Measurement Artifacts
A formal psychometric analysis shows that apparent psychological profiles of large language models are primarily driven by response bias, not actual traits. This bias, which shifts with model capability and is amplified by instrument design, accounts for 81-90% of between-model variation, far exceeding human trait differences. The study concludes that these profiles are artifacts of measurement and not model properties, urging the development of assessments based on response orthogonality.