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Main Authors: Wang, Xi, Zhuang, Mengdie, Liu, Jiqun
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2603.06088
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author Wang, Xi
Zhuang, Mengdie
Liu, Jiqun
author_facet Wang, Xi
Zhuang, Mengdie
Liu, Jiqun
contents Human problem-solving is enriched by a diversity of styles and personality traits, yet the development of Large Language Models (LLMs) has largely prioritized uniform performance benchmarks that favour specific behavioural tendencies such as assertiveness. To investigate how diverse experiences shape machine personality and influence problem-solving, this study employs continued pre-training to expose models to domain-specific texts in an unsupervised manner, simulating the accumulation of experience. By adapting the Big Five framework via the Machine Personality Inventory (MPI), we quantify the personality traits of these model variants and analyse their relationship to linguistic style and reasoning behaviour. The findings reveal that model competence is bimodal, peaking at "Expressive Generalists" and "Suppressed Specialists," while identifying a "Suppression Advantage" where reduced social traits enhance complex reasoning performance. This study further establishes a causal link between training data linguistics, such as imperative frequency, and lexical diversity, providing a roadmap for "Personality Engineering".
format Preprint
id arxiv_https___arxiv_org_abs_2603_06088
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Experiences Build Characters: The Linguistic Origins and Functional Impact of LLM Personality
Wang, Xi
Zhuang, Mengdie
Liu, Jiqun
Computation and Language
Artificial Intelligence
Human problem-solving is enriched by a diversity of styles and personality traits, yet the development of Large Language Models (LLMs) has largely prioritized uniform performance benchmarks that favour specific behavioural tendencies such as assertiveness. To investigate how diverse experiences shape machine personality and influence problem-solving, this study employs continued pre-training to expose models to domain-specific texts in an unsupervised manner, simulating the accumulation of experience. By adapting the Big Five framework via the Machine Personality Inventory (MPI), we quantify the personality traits of these model variants and analyse their relationship to linguistic style and reasoning behaviour. The findings reveal that model competence is bimodal, peaking at "Expressive Generalists" and "Suppressed Specialists," while identifying a "Suppression Advantage" where reduced social traits enhance complex reasoning performance. This study further establishes a causal link between training data linguistics, such as imperative frequency, and lexical diversity, providing a roadmap for "Personality Engineering".
title Experiences Build Characters: The Linguistic Origins and Functional Impact of LLM Personality
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2603.06088