  Humans possess the ability to draw on past experiences explicitly when
learning new tasks and applying them accordingly. We believe this capacity for
self-referencing is especially advantageous for reinforcement learning agents
in the unsupervised pretrain-then-finetune setting. During pretraining, an
agent's past experiences can be explicitly utilized to mitigate the
nonstationarity of intrinsic rewards. In the finetuning phase, referencing
historical trajectories prevents the unlearning of valuable exploratory
behaviors. Motivated by these benefits, we propose the Self-Reference (SR)
approach, an add-on module explicitly designed to leverage historical
information and enhance agent performance within the pretrain-finetune
paradigm. Our approach achieves state-of-the-art results in terms of
Interquartile Mean (IQM) performance and Optimality Gap reduction on the
Unsupervised Reinforcement Learning Benchmark for model-free methods, recording
an 86% IQM and a 16% Optimality Gap. Additionally, it improves current
algorithms by up to 17% IQM and reduces the Optimality Gap by 31%. Beyond
performance enhancement, the Self-Reference add-on also increases sample
efficiency, a crucial attribute for real-world applications.
