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bioRxiv · 10.64898/2026.10.07.757408

An Information Compass for Probabilistic Reasoning in the Brain

Bosulu, J.·Balasubramanian, V.·Kilpatrick, Z. P.·Josic, K.·Gold, J. I.
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Abstract

Probabilistic reasoning in the brain has been studied primarily using simple two-choice tasks that are experimentally and theoretically tractable but have unclear relevance to more complex problems. Here we generalize principles from these studies using information geometry, which treats probability distributions (``beliefs'') as points on statistical manifolds whose geometry captures relationships between those beliefs. We introduce an ``information compass,'' a context-dependent, one-dimensional axis along which an arbitrarily complex belief is reinforced or repudiated. Projecting high-dimensional belief updates onto this axis casts even complex decisions into familiar forms of deliberation and commitment used for simpler decisions. Our framework provides a unified account of how biological and artificial systems can use geometric forms of probabilistic reasoning to make decisions across a range of tasks and domains.

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Bosulu, J., Balasubramanian, V., Kilpatrick, Z. P., Josic, K., Gold, J. I.. 2026-10-14. An Information Compass for Probabilistic Reasoning in the Brain. https://doi.org/10.64898/2026.10.07.757408

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