FLamE: Few-shot Learning from Natural Language Explanations
Yangqiaoyu Zhou Yiming Zhang Chenhao Tan
Natural language explanations have the potential to provide rich information
that in principle guides model reasoning. Yet, recent work by Lampinen et al.
(2022) has shown limited utility of natural language explanations in improving
classification. To effectively learn from explanations, we present FLamE, a
two-stage few-shot learning framework that first generates explanations using
GPT-3, and then finetunes a smaller model (e.g., RoBERTa) with generated
explanations. Our experiments on natural language inference demonstrate
effectiveness over strong baselines, increasing accuracy by 17.6% over GPT-3
Babbage and 5.7% over GPT-3 Davinci in e-SNLI. Despite improving classification
performance, human evaluation surprisingly reveals that the majority of
generated explanations does not adequately justify classification decisions.
Additional analyses point to the important role of label-specific cues (e.g.,
"not know" for the neutral label) in generated explanations.