Double descent presents a counter-intuitive aspect within the machine learning domain, and researchers have observed its manifestation in various models and tasks. While some theoretical explanations have been proposed for this phenomenon in specific contexts, an accepted theory to account for its occurrence in deep learning remains yet to be established. In this study, we revisit the phenomenon of double descent and demonstrate that its occurrence is strongly influenced by the presence of noisy data. Through conducting a comprehensive analysis of the feature space of learned representations, we unveil that double descent arises in imperfect models trained with noisy data. We argue that double descent is a consequence of the model first learning the noisy data until interpolation and then adding implicit regularization via over-parameterization acquiring therefore capability to separate the information from the noise. We postulate that double descent should never occur in well-regularized models.

通过对学习表征的特征空间进行全面分析，我们揭示了双下降现象是在用带有噪声数据训练的不完美模型中产生的，它首先通过拟合噪声数据进行学习，然后通过超参数化添加隐式正则化，从而具备了将信息与噪声分离的能力。我们推断双下降现象不应该在经过良好正则化的模型中发生。

解开双下降之谜：通过学习特征空间的深入分析