Reasoning Promotes Robustness in Theory of Mind Tasks
Ian B. de Haan, Peter van der Putten, Max van Duijn
TL;DR
This work investigates whether RLVR-trained reasoning models truly expand theory-of-m mind abilities or primarily improve robustness to prompts in ToM tasks. By applying established ToM tests, novel prompt adaptations, and multiple benchmarks, the study finds that gains are largely due to more robust inference paths rather than novel ToM reasoning. Across psychological tests and literature benchmarks, reasoning models show markedly improved robustness to prompt variations, with some edge cases where limitations persist. The findings suggest a shift in how ToM performance should be interpreted in LLMs and highlight robustness as a key strength of RLVR-trained models. The work emphasizes careful benchmarking and prompts-aware evaluation to accurately assess social-cognitive capabilities in AI systems.
Abstract
Large language models (LLMs) have recently shown strong performance on Theory of Mind (ToM) tests, prompting debate about the nature and true performance of the underlying capabilities. At the same time, reasoning-oriented LLMs trained via reinforcement learning with verifiable rewards (RLVR) have achieved notable improvements across a range of benchmarks. This paper examines the behavior of such reasoning models in ToM tasks, using novel adaptations of machine psychological experiments and results from established benchmarks. We observe that reasoning models consistently exhibit increased robustness to prompt variations and task perturbations. Our analysis indicates that the observed gains are more plausibly attributed to increased robustness in finding the correct solution, rather than to fundamentally new forms of ToM reasoning. We discuss the implications of this interpretation for evaluating social-cognitive behavior in LLMs.
