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A steering vector is not the only option: clustered optimal-transport steering cut toxicity further, but a nearly constant map did almost as well

AspireAI community · arXiv (cs.AI)
The standard way to steer a language model's behavior is to add one vector, the difference of class means, to every hidden state, and this paper proves that no clustered optimal-transport map can differ from that vector except for tokens whose routing weights deviate from cluster sizes. A token-routing variant left 37-39% less toxicity than difference-of-means on Gemma-2-2B and 51-61% less on Granite-3.1-2B, and the advantage survived INT8 and NF4 quantization. The honest limitation is the authors' own: a nearly constant map from the same clusters also removed about 30% of toxicity, so the role of treating tokens differently remains genuinely open rather than settled.
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