让零样本模型在微调时避免学偏,提升鲁棒性。
StarFT: Robust Fine-tuning of Zero-shot Models via Spuriosity Alignment
- 通过注入虚假描述并正则化输出分布,防止模型学错特征。
- 在Waterbirds数据集上,最差组准确率提升14.30%,平均准确率提升3.02%。
- 适合需要高鲁棒性的下游任务,如小样本或分布偏移场景。
从数据中学习鲁棒表示通常需要大规模数据,这促成了近期零样本模型(如CLIP)的成功。然而,这些模型在其他下游任务(如小规模数据)上微调时,其鲁棒性容易下降。以往工作常从领域偏移角度解释此现象,提出保留原域的微调方法。但另一方面,小样本微调也易导致模型学习对人类无关的伪特征(如背景、纹理)。本文提出StarFT(Spurious Textual Alignment Regularization),一种通过防止模型学习伪特征来增强零样本模型鲁棒性的新框架。该方法引入正则化项,使包含伪特征的标签输出分布与原始零样本模型一致,避免模型进一步提取无关特征。利用最新语言模型生成强调潜在混淆特征的替代文本描述以构建伪特征标签。大量实验验证了StarFT的鲁棒泛化能力及其新特性:零样本组鲁棒性与改进的零样本分类性能。值得注意的是,在Waterbirds分布偏移场景中,StarFT将最差组和平均准确率分别提升14.30%和3.02%,而其他鲁棒微调基线甚至表现更差。
原文摘要 · Abstract (English)
Learning robust representations from data often requires scale, which has led to the success of recent zero-shot models such as CLIP. However, the obtained robustness can easily be deteriorated when these models are fine-tuned on other downstream tasks (e.g., of smaller scales). Previous works often interpret this phenomenon in the context of domain shift, developing fine-tuning methods that aim to preserve the original domain as much as possible. However, in a different context, fine-tuned models with limited data are also prone to learning features that are spurious to humans, such as background or texture. In this paper, we propose StarFT (Spurious Textual Alignment Regularization), a novel framework for fine-tuning zero-shot models to enhance robustness by preventing them from learning spuriosity. We introduce a regularization that aligns the output distribution for spuriosity-injected labels with the original zero-shot model, ensuring that the model is not induced to extract irrelevant features further from these descriptions. We leverage recent language models to get such spuriosity-injected labels by generating alternative textual descriptions that highlight potentially confounding features. Extensive experiments validate the robust generalization of StarFT and its emerging properties: zero-shot group robustness and improved zero-shot classification. Notably, StarFT boosts both worst-group and average accuracy by 14.30% and 3.02%, respectively, in the Waterbirds group shift scenario, where other robust fine-tuning baselines show even degraded performance.
Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品;中文卡片由大模型生成,请以原文为准。