Data Augmentation as Feature Manipulation

Understand

Data augmentation is a cornerstone of the machine learning pipeline, yet its theoretical underpinnings remain unclear.

• Is it merely a way to artificially augment the data set size? Or is it about encouraging the model to satisfy certain invariance? In this work we consider another angle, and we study the effect of data augmentation on the dynamic of the learning process.
• We find that data augmentation can alter the relative importance of various features, effectively making certain informative but hard to learn features more likely to be captured in the learning process.
• Importantly, we show that this effect is more pronounced for non-linear models, such as neural networks.