arXiv Machine Learning

The Value of Mechanistic Priors in Sequential Decision Making

arXiv Machine Learning
Aug 28

Safety by Design: Realized-Cost Constraints for Contextual Bandits with Continuous Actions

The paper introduces a new approach to safety in contextual bandits with continuous actions, focusing on high‑probability constraints on the realized cost rather than expected cost. It presents the High‑Probability Constrained UCB algorithm, which balances reward exploration with conservative safety estimation, and provides theoretical regret guarantees for linear models and extensions to general function classes. Experiments demonstrate that this realized‑cost safety framework significantly reduces safety violations compared to expected‑cost constrained methods.

By Spyros Dragazis, Aldo Pacchiano
Hugging Face Trending Papers
Aug 27

Safety by Design: Realized-Cost Constraints for Contextual Bandits with Continuous Actions

The paper introduces a new approach to safety in contextual bandits with continuous actions by enforcing high‑probability constraints on the realized cost rather than on its expectation. It proposes the High‑Probability Constrained UCB algorithm, which balances optimistic reward exploration with pessimistic safety estimation. The authors provide theoretical regret guarantees for linear models and extend the analysis to general function classes, demonstrating experimentally that realized‑cost constraints significantly reduce safety violations compared to expected‑cost baselines.

arXiv AI
Aug 26

Knowing When to Ask for Help: Bayesian Self-Escalation in Hierarchical LLM Agents

The paper introduces a Bayesian self‑escalation strategy for hierarchical large‑language‑model agents, allowing an agent to detect during its own reasoning that it is unlikely to succeed and hand control over to a stronger model. The authors formalise this as an optimal‑stopping problem over a learned competence posterior, derive a myopic escalation threshold, and prove that the optimal policy is a time‑varying threshold without assumptions on the raw signal. They provide theoretical guarantees—including a 1/√n regret decay with n calibration trajectories—and validate the approach in simulations and a real‑model code‑generation cascade, showing that the escalation frontier outperforms post‑hoc routing at equal cost. whyItMatters":"The study offers a principled, theoretically grounded method for agents to dynamically decide when to seek stronger models, potentially improving efficiency and reliability in hierarchical LLM systems."

By Nadeem Shaikh
arXiv AI
1d ago

Satisficing as competitive Bayesian weighting: a minimal model of goal-directed choice under an unattained target

The paper introduces Risk‑Sensitive Satisficing (RS), a bandit learning rule that evaluates actions based on their past frequency and their surplus or shortfall relative to an aspiration level. RS can be reformulated as Attention Competitive Bayes (ACB), a Bayesian‑like estimator where the aspiration level serves as a prior mean and the limited number of trials limits how strongly evidence can override this prior. ACB predicts that unchosen actions gradually revert toward the aspiration level (pseudo‑forgetting) and that when the aspiration is unattainable, exploration never fully settles, reducing regret in simulations.

By Moto Shinriki, Yu Kono, Tatsuji Takahashi
arXiv Machine Learning
Sep 30

NeuronSifter: Intervention Planning in CNS Microenvironments

NeuronSifter is a framework for planning interventions in central nervous system microenvironments by converting treatment regimens into state‑conditional target‑occupancy fields and propagating them through microenvironment dynamics. It selects measurements based on their expected reduction in intervention loss, integrating typed outcomes into a unified posterior. In synthetic Alzheimer’s disease scenarios, occupancy conditioning improves trajectory probability scores and intervention ordering accuracy, and decision‑directed acquisition reduces terminal risk compared to a Bayesian experimental design planner.

By Haowei Xu, Wanyi Fu, Hongbin Han, Zhaoheng Xie
arXiv AI
Sep 25

Policy Complexity, Reaction Time, and Bounded Rationality in Reinforcement Learning

The paper introduces MI‑SARSA, an on‑policy temporal‑difference algorithm that incorporates mutual‑information regularization to model bounded rationality in reinforcement learning. By penalizing state‑specific deviations from a learned marginal action prior, the algorithm selectively uses state information only when the expected return outweighs the informational cost, yielding a reward‑complexity tradeoff. MI‑SARSA also predicts reaction times, showing that stronger information penalties lead to simpler policies, lower control costs, and faster responses, while regularization mitigates performance loss after environmental shifts at the expense of asymptotic return.

By James Wu, Chris R. Sims
arXiv Machine Learning
Sep 3

On Cost-Aware Designs for Sequential Hypothesis Testing

The paper introduces Cost-Aware Sequential Hypothesis Testing (CASHT), where a decision-maker selects sensing actions with varying random costs to identify the true hypothesis under an average-error constraint while minimizing expected total cost. For fixed costs, the optimal expected total cost scales as Θ(log(1/δ)) and can be achieved by Multihypothesis Sequential Probability Ratio Test-based procedures. The authors extend the framework to random costs under ex-post and ex-ante revelation models, analyze when action cancellation reduces cost, and demonstrate through simulations that CA variants consistently lower total cost compared to classical methods.

By George Vershinin, Asaf Cohen, Omer Gurewitz