[2603.21398] Persona Vectors in Games: Measuring and Steering Strategies via Activation Vectors

Computer Science > Artificial Intelligence arXiv:2603.21398 (cs) [Submitted on 22 Mar 2026] Title:Persona Vectors in Games: Measuring and Steering Strategies via Activation Vectors Authors:Johnathan Sun, Andrew Zhang View a PDF of the paper titled Persona Vectors in Games: Measuring and Steering Strategies via Activation Vectors, by Johnathan Sun and 1 other authors View PDF HTML (experimental) Abstract:Large language models (LLMs) are increasingly deployed as autonomous decision-makers in strategic settings, yet we have limited tools for understanding their high-level behavioral traits. We use activation steering methods in game-theoretic settings, constructing persona vectors for altruism, forgiveness, and expectations of others by contrastive activation addition. Evaluating on canonical games, we find that activation steering systematically shifts both quantitative strategic choices and natural-language justifications. However, we also observe that rhetoric and strategy can diverge under steering. In addition, vectors for self-behavior and expectations of others are partially distinct. Our results suggest that persona vectors offer a promising mechanistic handle on high-level traits in strategic environments. Comments: Subjects: Artificial Intelligence (cs.AI); Computer Science and Game Theory (cs.GT) Cite as: arXiv:2603.21398 [cs.AI]   (or arXiv:2603.21398v1 [cs.AI] for this version)   https://doi.org/10.48550/arXiv.2603.21398 Focus to learn more arXiv-issued DOI via D...