Label-Agnostic Forgetting: A Supervision-Free Unlearning in Deep Models

TL;DR

This paper introduces Label-Agnostic Forgetting (LAF), a supervision-free method for unlearning in deep models that effectively removes information from forgotten data without requiring labels, using a variational and contrastive approach.

Contribution

The paper presents a novel supervision-free unlearning method that operates at the representation level, enabling effective data removal without label annotations and outperforming supervised baselines in semi-supervised settings.

Findings

LAF achieves comparable performance to supervised methods in unlearning tasks.

LAF outperforms fully supervised baselines in semi-supervised scenarios.

The approach effectively removes information from forgotten data without labels.

Abstract

Machine unlearning aims to remove information derived from forgotten data while preserving that of the remaining dataset in a well-trained model. With the increasing emphasis on data privacy, several approaches to machine unlearning have emerged. However, these methods typically rely on complete supervision throughout the unlearning process. Unfortunately, obtaining such supervision, whether for the forgetting or remaining data, can be impractical due to the substantial cost associated with annotating real-world datasets. This challenge prompts us to propose a supervision-free unlearning approach that operates without the need for labels during the unlearning process. Specifically, we introduce a variational approach to approximate the distribution of representations for the remaining data. Leveraging this approximation, we adapt the original model to eliminate information from the forgotten data at the representation level. To further address the issue of lacking supervision information, which hinders alignment with ground truth, we introduce a contrastive loss to facilitate the matching of representations between the remaining data and those of the original model, thus preserving predictive performance. Experimental results across various unlearning tasks demonstrate the effectiveness of our proposed method, Label-Agnostic Forgetting (LAF) without using any labels, which achieves comparable performance to state-of-the-art methods that rely on full supervision information. Furthermore, our approach excels in semi-supervised scenarios, leveraging limited supervision information to outperform fully supervised baselines. This work not only showcases the viability of supervision-free unlearning in deep models but also opens up a new possibility for future research in unlearning at the representation level.