RaVL: Discovering and Mitigating Spurious Correlations in Fine-Tuned
  Vision-Language Models
Authors: name: Maya Varma; name: Jean-Benoit Delbrouck; name: Zhihong Chen; name: Akshay Chaudhari; name: Curtis Langlotz
Published: 2024-11-06 18:25:00

Abstract: Fine-tuned vision-language models (VLMs) often capture spurious correlations
between image features and textual attributes, resulting in degraded zero-shot
performance at test time. Existing approaches for addressing spurious
correlations (i) primarily operate at the global image-level rather than
intervening directly on fine-grained image features and (ii) are predominantly
designed for unimodal settings. In this work, we present RaVL, which takes a
fine-grained perspective on VLM robustness by discovering and mitigating
spurious correlations using local image features rather than operating at the
global image level. Given a fine-tuned VLM, RaVL first discovers spurious
correlations by leveraging a region-level clustering approach to identify
precise image features contributing to zero-shot classification errors. Then,
RaVL mitigates the identified spurious correlation with a novel region-aware
loss function that enables the VLM to focus on relevant regions and ignore
spurious relationships during fine-tuning. We evaluate RaVL on 654 VLMs with
various model architectures, data domains, and learned spurious correlations.
Our results show that RaVL accurately discovers (191% improvement over the
closest baseline) and mitigates (8.2% improvement on worst-group image
classification accuracy) spurious correlations. Qualitative evaluations on
general-domain and medical-domain VLMs confirm our findings.