Improving In-Context Few-Shot Learning via Self-Supervised Training
Mingda Chen, Jingfei Du, Ramakanth Pasunuru, Todor Mihaylov, Srini Iyer, Veselin Stoyanov, Zornitsa Kozareva
TL;DR
The paper tackles improving in-context few-shot learning by inserting an intermediate self-supervised training stage between pretraining and downstream evaluation. It introduces four objectives—Next Sentence Generation, Masked Word Prediction, Last Phrase Prediction, and Classification—to train models in formats aligned with downstream tasks. Experiments on SuperGLUE and Natural-Instructions show that this intermediate self-supervision yields the best average performance, with benefits modulated by data amount, objective diversity, and template similarity; cross-task human supervision is complementary. The approach demonstrates a practical pathway to tailor pretraining for few-shot tasks without additional labeled data, improving instruction-following and task compliance in generated outputs.
Abstract
Self-supervised pretraining has made few-shot learning possible for many NLP tasks. But the pretraining objectives are not typically adapted specifically for in-context few-shot learning. In this paper, we propose to use self-supervision in an intermediate training stage between pretraining and downstream few-shot usage with the goal to teach the model to perform in-context few shot learning. We propose and evaluate four self-supervised objectives on two benchmarks. We find that the intermediate self-supervision stage produces models that outperform strong baselines. Ablation study shows that several factors affect the downstream performance, such as the amount of training data and the diversity of the self-supervised objectives. Human-annotated cross-task supervision and self-supervision are complementary. Qualitative analysis suggests that the self-supervised-trained models are better at following task requirements.
