The Representation-Rationalizability Tradeoff in Reward Learning
In RLHF, each training example contains a prompt $x$ and two candidate responses $y,y'$, and annotators provide pairwise preferences between these responses. The learning problem is to convert these heterogeneous pairwise judgments into a single scalar reward $r(x,y)$ that measures response quality for each prompt. Classical social choice implies an impossibility because heterogeneous annotator samples can induce pooled preferences with Condorcet cycles, so no scalar reward can evaluate all compared response pairs consistently. A growing literature analyzes RLHF as a social-choice problem, but usually assumes a fixed finite set of alternatives, i.e., a pre-enumerated finite set of candida...
| Authors | Jing Dong, Yaoliang Yu, Pascal Pourpart |
|---|---|
| Primary category | cs.GT |
| Published | 29 May 2026 |
| Last updated at source | 29 May 2026 |
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