The continual learning setting aims to learn new tasks over time without forgetting the previous ones. The literature reports several significant efforts to tackle this problem with limited or no access to previous task data. Among such efforts, typical solutions offer sophisticated techniques involving memory replay, knowledge distillation, model regularization, and dynamic network expansion. The resulting methods have a retraining cost at each learning task, dedicated memory requirements, and setting-specific design choices. In this work, we show that a frozen CLIP (Contrastive Language-Image Pretraining) model offers astounding continual learning performance without any fine-tuning (zero-shot evaluation). We evaluate CLIP under a variety of settings including class-incremental, domain-incremental and task-agnostic incremental learning on five popular benchmarks (ImageNet-100 & 1K, CORe50, CIFAR-100, and TinyImageNet). Without any bells and whistles, the CLIP model outperforms the state-of-the-art continual learning approaches in the majority of the settings. We show the effect on the CLIP model's performance by varying text inputs with simple prompt templates. To the best of our knowledge, this is the first work to report the CLIP zero-shot performance in a continual setting. We advocate the use of this strong yet embarrassingly simple baseline for future comparisons in the continual learning tasks.

本文发现，CLIP（Contrastive Language-Image Pretraining）模型在冻结状态下，在不进行任何微调（零次评估）的情况下提供惊人的持续学习表现。作者在多种设置（包括类增量、域增量和任务不可知的增量学习）和五个流行基准测试集上评估了CLIP模型，证明了其在大多数设置中优于现有模型；同时作者还通过改变简单提示模板的文本输入来研究CLIP模型性能的影响。作者鼓励在持续学习任务中使用这种强大而非常简单的基线方法进行未来的比较。

CLIP模型是高效的继续学习器