  Reinforcement learning from human feedback (RLHF) enables machine learning
systems to learn objectives from human feedback. A core limitation of these
systems is their assumption that all feedback comes from a single human
teacher, despite querying a range of distinct teachers. We propose the Hidden
Utility Bandit (HUB) framework to model differences in teacher rationality,
expertise, and costliness, formalizing the problem of learning from multiple
teachers. We develop a variety of solution algorithms and apply them to two
real-world domains: paper recommendation systems and COVID-19 vaccine testing.
We find that the Active Teacher Selection (ATS) algorithm outperforms baseline
algorithms by actively selecting when and which teacher to query. The HUB
framework and ATS algorithm demonstrate the importance of leveraging
differences between teachers to learn accurate reward models, facilitating
future research on active teacher selection for robust reward modeling.
