低资源语言安全拒绝对话失败,源于判断校准失效而非表征缺失。
Low-Resource Safety Failures Are Action Failures, Not Representation Failures

- 通过重校准高资源语言的决策阈值,修复低资源语言的安全判断。
- 仅需1-4个目标语言样本,拒绝率从43.9%提升至54.5%。
- 适合解决低资源语言安全对齐问题的研究者与实践者。
在高资源语言中训练的安全对齐模型在低资源语言中表现不佳:模型在英语中能拒绝有害提示,但相同提示翻译成斯瓦希里语或缅甸语后却无法拒绝。自适应调制方法如AdaSteer和CAST也继承了这一跨语言失效问题。我们诊断发现,从高资源激活中提取的有害性方向,在23种语言的低资源提示中仍能近乎等效地分离有害与无害样本(高资源与低资源分离效果相近)。然而,有害拒绝率从87.9%骤降至43.9%,说明问题出在安全决策的校准,而非表征本身。我们提出仅通过重设一个低秩逻辑读出层的决策阈值(利用每类1-4个目标语言样本),即可显著提升拒绝选择性(Δ = 有害拒绝 - 无害拒绝)从33.6升至54.5,同时保持MMLU任务性能。结果表明,部分低资源安全失效可通过校准现有表征修复,无需重新训练。代码已开源:https://github.com/rashadaziz/low-resource-safety。
原文摘要 · Abstract (English)
Safety alignment learned in high-resource languages transfers poorly to low-resource languages. Models refuse harmful prompts in English but fail to refuse when the same prompts are translated into Swahili or Burmese. Adaptive steering methods like AdaSteer and CAST inherit this failure cross-lingually. We diagnose where transfer breaks down. Across Qwen2.5-7B, Gemma-2-9B, and Llama-3.1-8B on 23 languages, the harmfulness direction extracted from high-resource activations linearly separates harmful from harmless low-resource prompts nearly as well as high-resource ones. The relevant representation is present. Yet harmful refusal drops from 87.9% to 43.9%. The model fails to convert the representation into refusal. What fails to transfer is calibration of the safety decision, not the underlying representation. We exploit this by recalibrating, rather than retraining, a high-resource gate: a low-rank logistic readout with its decision threshold reset using as few as 1 to 4 target-language examples per class. The gate routes between refusal steering and harmfulness-direction ablation, substantially raising mean refusal selectivity ($Δ$ = harmful $-$ harmless refusal) from 33.6 for the strongest adapted baseline to 54.5 while preserving MMLU utility. These results suggest that some low-resource safety failures can be repaired by recalibrating existing representations rather than learning new ones. Our code is released: https://github.com/rashadaziz/low-resource-safety.
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