Features as Rewards: Scalable Supervision for Open-Ended Tasks via Interpretability

Fuente: arXiv
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Main Authors: Prasad, Aaditya Vikram, Watts, Connor, Merullo, Jack, Gala, Dhruvil, Lewis, Owen, McGrath, Thomas, Lubana, Ekdeep Singh
Format: Preprint
Published: 2026
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author Prasad, Aaditya Vikram
Watts, Connor
Merullo, Jack
Gala, Dhruvil
Lewis, Owen
McGrath, Thomas
Lubana, Ekdeep Singh
author_facet Prasad, Aaditya Vikram
Watts, Connor
Merullo, Jack
Gala, Dhruvil
Lewis, Owen
McGrath, Thomas
Lubana, Ekdeep Singh
contents Language models trained on large-scale datasets have been shown to learn features that encode abstract concepts such as factuality or intent. Such features are traditionally used for test-time monitoring or steering. We present an alternative affordance: features as scalable supervision for open-ended tasks. We consider the case of hallucination-reduction as a desirable, yet open-ended behavior and design a reinforcement learning (RL) pipeline, titled RLFR (Reinforcement Learning from Feature Rewards), that uses features as reward functions. Grounded in a novel probing framework that identifies candidate hallucinated claims, our pipeline teaches a model to intervene and correct its completions when it is uncertain of their factuality. Furthermore, the pipeline enables scalable test-time compute, guided once more by our reward features. This end-to-end process operationalized on Gemma-3-12B-IT results in a policy that is 58% less likely to hallucinate compared to the original model (when run in tandem with our probing harness), while preserving performance on standard benchmarks. Taken together, by grounding supervision in the language of features, this paper introduces a novel paradigm in the use of interpretability for learning open-ended tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2602_10067
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Features as Rewards: Scalable Supervision for Open-Ended Tasks via Interpretability
Prasad, Aaditya Vikram
Watts, Connor
Merullo, Jack
Gala, Dhruvil
Lewis, Owen
McGrath, Thomas
Lubana, Ekdeep Singh
Machine Learning
Language models trained on large-scale datasets have been shown to learn features that encode abstract concepts such as factuality or intent. Such features are traditionally used for test-time monitoring or steering. We present an alternative affordance: features as scalable supervision for open-ended tasks. We consider the case of hallucination-reduction as a desirable, yet open-ended behavior and design a reinforcement learning (RL) pipeline, titled RLFR (Reinforcement Learning from Feature Rewards), that uses features as reward functions. Grounded in a novel probing framework that identifies candidate hallucinated claims, our pipeline teaches a model to intervene and correct its completions when it is uncertain of their factuality. Furthermore, the pipeline enables scalable test-time compute, guided once more by our reward features. This end-to-end process operationalized on Gemma-3-12B-IT results in a policy that is 58% less likely to hallucinate compared to the original model (when run in tandem with our probing harness), while preserving performance on standard benchmarks. Taken together, by grounding supervision in the language of features, this paper introduces a novel paradigm in the use of interpretability for learning open-ended tasks.
title Features as Rewards: Scalable Supervision for Open-Ended Tasks via Interpretability
topic Machine Learning
url https://arxiv.org/abs/2602.10067