Self-Assessment Tests are Unreliable Measures of LLM Personality

Akshat Gupta, Xiaoyang Song, Gopala Anumanchipalli


Abstract
As large language models (LLM) evolve in their capabilities, various recent studies have tried to quantify their behavior using psychological tools created to study human behavior. One such example is the measurement of “personality” of LLMs using self-assessment personality tests developed to measure human personality. Yet almost none of these works verify the applicability of these tests on LLMs. In this paper, we analyze the reliability of LLM personality scores obtained from self-assessment personality tests using two simple experiments. We first introduce the property of prompt sensitivity, where three semantically equivalent prompts representing three intuitive ways of administering self-assessment tests on LLMs are used to measure the personality of the same LLM. We find that all three prompts lead to very different personality scores, a difference that is statistically significant for all traits in a large majority of scenarios. We then introduce the property of option-order symmetry for personality measurement of LLMs. Since most of the self-assessment tests exist in the form of multiple choice question (MCQ) questions, we argue that the scores should also be robust to not just the prompt template but also the order in which the options are presented. This test unsurprisingly reveals that the self-assessment test scores are not robust to the order of the options. These simple tests, done on ChatGPT and three Llama2 models of different sizes, show that self-assessment personality tests created for humans are unreliable measures of personality in LLMs.
Anthology ID:
2024.blackboxnlp-1.20
Volume:
Proceedings of the 7th BlackboxNLP Workshop: Analyzing and Interpreting Neural Networks for NLP
Month:
November
Year:
2024
Address:
Miami, Florida, US
Editors:
Yonatan Belinkov, Najoung Kim, Jaap Jumelet, Hosein Mohebbi, Aaron Mueller, Hanjie Chen
Venue:
BlackboxNLP
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
301–314
Language:
URL:
https://aclanthology.org/2024.blackboxnlp-1.20
DOI:
Bibkey:
Cite (ACL):
Akshat Gupta, Xiaoyang Song, and Gopala Anumanchipalli. 2024. Self-Assessment Tests are Unreliable Measures of LLM Personality. In Proceedings of the 7th BlackboxNLP Workshop: Analyzing and Interpreting Neural Networks for NLP, pages 301–314, Miami, Florida, US. Association for Computational Linguistics.
Cite (Informal):
Self-Assessment Tests are Unreliable Measures of LLM Personality (Gupta et al., BlackboxNLP 2024)
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PDF:
https://aclanthology.org/2024.blackboxnlp-1.20.pdf