Equal reward weighting can steer language models toward easier shortcuts

The authors characterize how auxiliary rewards can displace task performance and propose a gating rule that prioritizes a more trusted reward channel.

Big Tech
Yushu Li · Jiin Woo · Xiaoxiao Li · Youngsuk Park

University of British Columbia · Amazon Annapurna Labs

Research Digest··3 min read
Li and colleagues show that combining a primary reward, such as correctness, with an easier auxiliary reward, such as brevity, can raise the aggregate training objective while reducing task success.

The authors formulate multi-reward post-training as a one-step stochastic decision problem.

Why this paper

From Amazon Annapurna Labs and University of British Columbia

In one line

Symmetric reward aggregation in LLM post-training degrades primary task performance by favoring easier auxiliary rewards.

What we could check

  • ·No code link found
  • ·No weights link found
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  • ✓Limitations stated by the authors (3 noted)
  • ✓Reports numbers on named benchmarks

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Research Digest

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