John Langford
2026
EnsemW2S: Enhancing Weak-to-Strong Generalization with Large Language Model Ensembles
Aakriti Agrawal | Mucong Ding | Chenghao Deng | Zora Che | Arjun Rajaram | Anirudh Satheesh | Bang An | C. Bayan Bruss | John Langford | Furong Huang
Findings of the Association for Computational Linguistics: ACL 2026
Aakriti Agrawal | Mucong Ding | Chenghao Deng | Zora Che | Arjun Rajaram | Anirudh Satheesh | Bang An | C. Bayan Bruss | John Langford | Furong Huang
Findings of the Association for Computational Linguistics: ACL 2026
With Large Language Models (LLMs) rapidly approaching and potentially surpassing human-level performance, it has become imperative to develop approaches capable of effectively supervising and enhancing these powerful models using smaller, human-level models exposed to only human-level data. We address this critical weak-to-strong (W2S) generalization challenge by proposing a novel method aimed at improving weak experts, by training on the same limited human-level data, enabling them to generalize to complex, super-human-level tasks. Our approach, called EnsemW2S, employs a token-level ensemble strategy that iteratively combines multiple weak experts, systematically addressing the shortcomings identified in preceding iterations. By continuously refining these weak models, we significantly enhance their collective ability to supervise stronger student models. We extensively evaluate the generalization performance of both the ensemble of weak experts and the subsequent strong student model across in-distribution (ID) and out-of-distribution (OOD) datasets. For OOD, we specifically introduce question difficulty as an additional dimension for defining distributional shifts. Our empirical results demonstrate notable improvements, achieving 4%, and 3.2% improvements on ID datasets and, upto 6% and 2.28% on OOD datasets for experts and student models respectively, underscoring the effectiveness of our proposed method in advancing W2S generalization.
2017
Mapping Instructions and Visual Observations to Actions with Reinforcement Learning
Dipendra Misra | John Langford | Yoav Artzi
Proceedings of the 2017 Conference on Empirical Methods in Natural Language Processing
Dipendra Misra | John Langford | Yoav Artzi
Proceedings of the 2017 Conference on Empirical Methods in Natural Language Processing
We propose to directly map raw visual observations and text input to actions for instruction execution. While existing approaches assume access to structured environment representations or use a pipeline of separately trained models, we learn a single model to jointly reason about linguistic and visual input. We use reinforcement learning in a contextual bandit setting to train a neural network agent. To guide the agent’s exploration, we use reward shaping with different forms of supervision. Our approach does not require intermediate representations, planning procedures, or training different models. We evaluate in a simulated environment, and show significant improvements over supervised learning and common reinforcement learning variants.