Summary
This paper proposes Read and Reward (RR), a method to incorporate prior human knowledge about the environment to achieve performance and efficiency gains in RL environments. The paper instantiates RR in several Atari environments by reading the information from the instruction manual. A full end-to-end pipeline is demonstrated on Skiing and a pipeline without object detection is demonstrated on Tennis, Pacman, and Breakout.
Strengths
*Originality*: While incorporating prior knowledge into RL training is a previously investigated topic, this paper provides an end-to-end pipeline and demonstrates its usefulness on Atari Skiing. The method introduced is more general than methods previously investigated.
*Quality*: There are thorough experiments with ablation studies, such as training the QA module on a different set of instructions.
*Clarity*: the paper is well-written.
*Significance*: as RL agents are eventually deployed in real-world scenarios, it will be increasingly important to have them learn efficiently and incorporate prior knowledge, which is often in the form of text. This paper provides a complete demonstration of a method leveraging natural language data to improve performance. More generally, it sketches out a framework for exploiting external data that future algorithms may build upon. Such agents may be rapidly deployed to learn in an unsupervised fashion.
Weaknesses
Although RR is an interesting proof-of-concept of automated reward shaping, it is unclear whether it scales to more complex environments or works on noisier sources of textual knowledge. In particular:
1. Does RR generalize to noisier sources of textual data? While the Wikipedia ablation is interesting, the data itself is rather clean and contains similar information. One interesting experiment to try might be with text-based RL environments, such as the Jericho [1] or Machiavelli [2] environments. Oftentimes these environments have publicly available [walkthroughs online](https://forum.choiceofgames.com/t/guides-for-all-games/15569/4), although they are often incomplete and noisy, as the instructions are intended for humans. Is RR able to extract the rewards and guide the agents in this setting? (I realize that this would be a significant undertaking so am not expecting it in the rebuttal)
2. The reward shaping only surrounds object detection. As a result, the QA prompt, even though it is hand-designed, still generalizes. However, there are several RL environments where the rewards are more heuristics rather than strict rules. For example, dialogue in the Diplomacy environment [3] does not have clear positive or negative reward but instead depends on the context. One could imagine gaining better understanding of dialogue in Diplomacy by leveraging knowledge on the internet, but it is unclear how RR might be applied in that scenario, as the reward shaping must center on text and the QA prompt likely could not be hand-designed.
3. It seems like it was quite difficult to train a bounding-box detector for most games. However, this would imply that RR's capabilities are bottlenecked by limitations of such bounding-box detectors. This might make RR difficult to scale to more complex environments with more ambiguous objects.
[1] Hausknecht, M., Ammanabrolu, P., Coté Marc-Alexandre, & Yuan Xingdi (2019). Interactive Fiction Games: A Colossal Adventure. CoRR, abs/1909.05398.
[2] Pan, A., Chan, J., Zou, A., Li, N., Basart, S., Woodside, T., Ng, J., Zhang, H., Emmons, S., & Hendrycks, D. (2023). Do the Rewards Justify the Means? Measuring Trade-Offs Between Rewards and Ethical Behavior in the Machiavelli Benchmark. ICML.
[3] Meta Fundamental AI Research Diplomacy Team (FAIR) et al. Human-level play in the game of Diplomacy by combining language models with strategic reasoning. Science 378,1067-1074 (2022). DOI:10.1126/science.ade9097
Questions
1. Would it be possible to have more results on other Atari games? I understand that the bounding-box detection was challenging, but are Tennis, Pacman, and Breakout the only other Atari games that allow for ground truth calculation of the objects from the RAM state?
2. How robust is the automated reward shaping to the quality of the bounding box detector in Skiing?
Rating
6: Weak Accept: Technically solid, moderate-to-high impact paper, with no major concerns with respect to evaluation, resources, reproducibility, ethical considerations.
Confidence
4: You are confident in your assessment, but not absolutely certain. It is unlikely, but not impossible, that you did not understand some parts of the submission or that you are unfamiliar with some pieces of related work.
Limitations
While some limitations are addressed, it would be interesting if there were additional discussion about the limitations of extracting information from natural language data. For example, humans understanding of the physical world may not be adequately encoded in natural language. Does this limit the application scope of agents using the RR method? Additionally, if the LM's reasoning abilities are erroneous, will this irreparably break RR?
Finally, it would be helpful to directly note that as RR is fundamentally a reward shaping method, it is difficult to apply it to situations where the reward itself is unclear. This happens often with delayed reward. In particular, RR would likely not improve performance on Go or Chess.