Is Self-Supervised Contrastive Learning More Robust Than Supervised Learning?

Self-supervised contrastive pre-training is a powerful tool to learn visual representation without human labels. Prior works have primarily focused on the recognition accuracy of contrastive learning but have overlooked other behavioral aspects. Besides accuracy, robustness plays a critical role in machine learning's reliability. We design and conduct a series of robustness tests to quantify the robustness difference between contrastive learning and supervised learning. These tests leverage data corruptions at multiple levels, ranging from pixel-level to patch-level and dataset-level, of either downstream or pre-training data. Our tests unveil intriguing robustness behaviors of contrastive and supervised learning. On one hand, under downstream corruptions, contrastive learning is surprisingly more robust than supervised learning. On the other hand, under pre-training corruptions, contrastive learning is vulnerable to patch shuffling and pixel intensity change, yet less sensitive to dataset-level distribution change. We analyze these results through the role of data augmentation and feature properties which have implications on improving supervised pre-training's downstream robustness.