Rigidity in LLM Bandits with Implications for Human-AI Dyads

Fuente: arXiv
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Hauptverfasser: Wang, Haomiaomiao, Ward, Tomás E, Zhang, Lili
Format: Preprint
Veröffentlicht: 2026
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author Wang, Haomiaomiao
Ward, Tomás E
Zhang, Lili
author_facet Wang, Haomiaomiao
Ward, Tomás E
Zhang, Lili
contents We test whether LLMs show robust decision biases. Treating models as participants in two-arm bandits, we ran 20000 trials per condition across four decoding configurations. Under symmetric rewards, models amplified positional order into stubborn one-arm policies. Under asymmetric rewards, they exploited rigidly yet underperformed an oracle and rarely re-checked. The observed patterns were consistent across manipulations of temperature and top-p, with top-k held at the provider default, indicating that the qualitative behaviours are robust to the two decoding knobs typically available to practitioners. Crucially, moving beyond descriptive metrics to computational modelling, a hierarchical Rescorla-Wagner-softmax fit revealed the underlying strategies: low learning rates and very high inverse temperatures, which together explain both noise-to-bias amplification and rigid exploitation. These results position minimal bandits as a tractable probe of LLM decision tendencies and motivate hypotheses about how such biases could shape human-AI interaction.
format Preprint
id arxiv_https___arxiv_org_abs_2603_07717
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Rigidity in LLM Bandits with Implications for Human-AI Dyads
Wang, Haomiaomiao
Ward, Tomás E
Zhang, Lili
Artificial Intelligence
Computer Science and Game Theory
Human-Computer Interaction
We test whether LLMs show robust decision biases. Treating models as participants in two-arm bandits, we ran 20000 trials per condition across four decoding configurations. Under symmetric rewards, models amplified positional order into stubborn one-arm policies. Under asymmetric rewards, they exploited rigidly yet underperformed an oracle and rarely re-checked. The observed patterns were consistent across manipulations of temperature and top-p, with top-k held at the provider default, indicating that the qualitative behaviours are robust to the two decoding knobs typically available to practitioners. Crucially, moving beyond descriptive metrics to computational modelling, a hierarchical Rescorla-Wagner-softmax fit revealed the underlying strategies: low learning rates and very high inverse temperatures, which together explain both noise-to-bias amplification and rigid exploitation. These results position minimal bandits as a tractable probe of LLM decision tendencies and motivate hypotheses about how such biases could shape human-AI interaction.
title Rigidity in LLM Bandits with Implications for Human-AI Dyads
topic Artificial Intelligence
Computer Science and Game Theory
Human-Computer Interaction
url https://arxiv.org/abs/2603.07717