Summary
This work addresses zero-shot reinforcement learning (RL), focusing on training agents to perform tasks without explicit rewards during pre-training. The authors investigate the performance degradation that occurs with small, homogeneous datasets and propose conservative zero-shot RL algorithms inspired by single-task offline RL approaches. Experimental results demonstrate that the proposed methods improve performance on sub-optimal datasets without compromising effectiveness on large, diverse datasets.
Strengths
* Zero-shot pretraining for RL is a crucial problem that can enhance generalization in downstream tasks.
* The proposed method is well-motivated, and the writing is clear.
* The experiments are thorough and effectively validate the proposed method.
Weaknesses
* One weakness of the paper is the lack of a clear definition for "low-quality data." As shown in Figure 8, it might be more accurately described as "coverage" rather than quality. Providing a more explicit definition is recommended.
* Additionally, the comparison of baselines is incomplete, as it lacks an offline goal-conditioned baseline, which is highly relevant in the considered tasks. Including a representative offline GCRL baseline, such as GC-IQL, would strengthen the comparison.
* Some related works are missing, particularly in the offline GCRL domain. References [1][2][3][4] are pertinent as they also focus on learning from offline datasets without rewards and deploying for multiple goals. The didactic example in this paper is very similar to Figure 1 in a prior paper [3], which also convey similar information during zero-shot deployment for multiple goals. A discussion with the prior results would be beneficial. Furthermore, a very relevant offline zero-shot RL method [5] is neither cited nor discussed.
*References*
[1] Yang R, Lu Y, Li W, et al. Rethinking goal-conditioned supervised learning and its connection to offline rl. ICLR, 2022.
[2] Park S, Ghosh D, Eysenbach B, et al. Hiql: Offline goal-conditioned rl with latent states as actions. Advances in Neural Information Processing Systems, 2024.
[3] Yang R, Yong L, Ma X, et al. What is essential for unseen goal generalization of offline goal-conditioned rl?[C]//International Conference on Machine Learning. PMLR, 2023.
[4] Eysenbach B, Zhang T, Levine S, et al. Contrastive learning as goal-conditioned reinforcement learning[J]. Advances in Neural Information Processing Systems, 2022.
[5] Frans K, Park S, Abbeel P, et al. Unsupervised Zero-Shot Reinforcement Learning via Functional Reward Encodings[J]. arXiv preprint arXiv:2402.17135, 2024.
Questions
* Could the authors provide a more explicit definition of "low-quality data"?
* It is recommended to compare the proposed method with a representative offline GCRL baseline.
* Including related works discussed above would make this study more comprehensive.
* Can this method also be applied to approaches based on successor features?