Augmentations vs Algorithms: What Works in Self-Supervised Learning
Warren Morningstar Alex Bijamov Chris Duvarney Luke Friedman Neha Kalibhat Luyang Liu Philip Mansfield Renan Rojas-Gomez Karan Singhal Bradley Green Sushant Prakash
We study the relative effects of data augmentations, pretraining algorithms,
and model architectures in Self-Supervised Learning (SSL). While the recent
literature in this space leaves the impression that the pretraining algorithm
is of critical importance to performance, understanding its effect is
complicated by the difficulty in making objective and direct comparisons
between methods. We propose a new framework which unifies many seemingly
disparate SSL methods into a single shared template. Using this framework, we
identify aspects in which methods differ and observe that in addition to
changing the pretraining algorithm, many works also use new data augmentations
or more powerful model architectures. We compare several popular SSL methods
using our framework and find that many algorithmic additions, such as
prediction networks or new losses, have a minor impact on downstream task
performance (often less than $1\%$), while enhanced augmentation techniques
offer more significant performance improvements ($2-4\%$). Our findings
challenge the premise that SSL is being driven primarily by algorithmic
improvements, and suggest instead a bitter lesson for SSL: that augmentation
diversity and data / model scale are more critical contributors to recent
advances in self-supervised learning.