AD-DROP: Attribution-Driven Dropout for Robust Language Model Fine-Tuning

Tao Yang, Jinghao Deng, Xiaojun Quan, Qifan Wang, Shaoliang Nie

Keywords: dropout, self-attention, attribution, fine-tune, language model

TL;DR: We investigate the impact of dropout on self-attention and propose a novel dropout regularizer, AD-DROP, driven by self-attention attribution to reduce overfitting when fine-tuning pre-trained language models.

Abstract: Fine-tuning large pre-trained language models on downstream tasks is apt to suffer from overfitting when limited training data is available. While dropout proves to be an effective antidote by randomly dropping a proportion of units, existing research has not examined its effect on the self-attention mechanism. In this paper, we investigate this problem through self-attention attribution and find that dropping attention positions with low attribution scores can accelerate training and increase the risk of overfitting. Motivated by this observation, we propose Attribution-Driven Dropout (AD-DROP), which randomly discards some high-attribution positions to encourage the model to make predictions by relying more on low-attribution positions to reduce overfitting. We also develop a cross-tuning strategy to alternate fine-tuning and AD-DROP to avoid dropping high-attribution positions excessively. Extensive experiments on various benchmarks show that AD-DROP yields consistent improvements over baselines. Analysis further confirms that AD-DROP serves as a strategic regularizer to prevent overfitting during fine-tuning.