Utilizing Inherent Bias for Memory Efficient Continual Learning: A Simple and Robust Baseline

Abstract

Learning from continuously evolving data is critical in real-world applications. This type of learning, known as Continual Learning (CL), aims to assimilate new information without compromising performance on prior knowledge. However, learning new information leads to a bias in the network towards recent observations, resulting in a phenomenon known as catastrophic forgetting. The complexity increases in Online Continual Learning (OCL) scenarios where models are allowed only a single pass over data. Existing OCL approaches that rely on replaying exemplar sets are not only memory-intensive when it comes to large-scale datasets but also raise security concerns. While recent dynamic network models address memory concerns, they often present computationally demanding, over-parameterized solutions with limited generalizability. To address this longstanding problem, we propose a novel OCL approach termed “Bias Robust online Continual Learning (BRCL).” BRCL retains all intermediate models generated. These models inherently exhibit a preference for recently learned classes. To leverage this property for enhanced performance, we devise a strategy we describe as ‘utilizing bias to counteract bias.’ This method involves the development of an Inference function that capitalizes on the inherent biases of each model towards the recent tasks. Furthermore, we integrate a model consolidation technique that aligns the first layers of these models, particularly focusing on similar feature representations. This process effectively reduces the memory requirement, ensuring a low memory footprint. Despite the simplicity of the methodology to guarantee expandability to various frameworks, extensive experiments reveal a notable performance edge over leading methods on key benchmarks, getting continual learning closer to matching offline training. (Source code will be made publicly available upon the publication of this paper.)