The History and Risks of Reinforcement Learning and Human Feedback (2310.13595v2)

Abstract: Reinforcement learning from human feedback (RLHF) has emerged as a powerful technique to make LLMs easier to use and more effective. A core piece of the RLHF process is the training and utilization of a model of human preferences that acts as a reward function for optimization. This approach, which operates at the intersection of many stakeholders and academic disciplines, remains poorly understood. RLHF reward models are often cited as being central to achieving performance, yet very few descriptors of capabilities, evaluations, training methods, or open-source models exist. Given this lack of information, further study and transparency is needed for learned RLHF reward models. In this paper, we illustrate the complex history of optimizing preferences, and articulate lines of inquiry to understand the sociotechnical context of reward models. In particular, we highlight the ontological differences between costs, rewards, and preferences at stake in RLHF's foundations, related methodological tensions, and possible research directions to improve general understanding of how reward models function.

A Systematic Examination of Reinforcement Learning from Human Feedback (RLHF)

The paper "The History and Risks of Reinforcement Learning and Human Feedback" presents a comprehensive analysis of the theoretical foundations and practical implementations of Reinforcement Learning from Human Feedback (RLHF). The authors, Nathan Lambert, Thomas Krendl Gilbert, and Tom Zick, delve into the historical and intellectual lineage that informs RLHF, critically addressing the assumptions and presumptions inherent in the process of modeling and optimizing human preferences.

The paper is significant as it emphasizes the lack of transparency and understanding surrounding RLHF reward models, which are central to the performance of LLMs equipped with human-like interaction capabilities, such as OpenAI's ChatGPT and Anthropic's Claude. The authors argue for improved clarity and methodological inquiry into the design and deployment of these models, foregrounding the sociotechnical context involved.

The core contribution of the paper lies in its historical tracing of RLHF's intellectual ancestry, linking the evolution of preference quantification to modern reinforcement learning. The authors detail the historical convergences that have shaped the existing RLHF framework, identifying key assumptions that underpin current methodologies. Among these assumptions are the quantifiability of human preferences, the presupposition that optimal solutions exist for stated optimization problems, and the notion that the reward signal accurately captures user preferences without compromising their complexity and variability.

The authors underscore that despite RLHF drawing from mature fields like control theory and behavioral economics, the method faces issues when it comes to human preference modeling, as preferences are inherently contextual, temporal, and often ambiguous. This raises critical questions about whether the aggregation of binary pairwise preferences into a single reward model truly reflects human values across diverse contexts and populations.

Moreover, the paper provides a scholarly discussion on specific assumptions and presumptions ranging from the representational adequacy of pairwise preferences, the conflation of human values and reward functions, to the methodological tensions in reinforcement learning algorithms derived from disparate disciplinary origins. Implicit biases in data collection and model training further complicate the use of RLHF, requiring interrogation into the demographics and contexts of the data annotation processes.

In terms of methodological development, the authors propose a series of questions related to model training, data curation, and optimization practices, urging researchers to systematically evaluate reward models’ capabilities and potential hazards. The importance of clear documentation, rigorous testing protocols, and thoughtful contextual consideration is highlighted in proposing more robust model evaluation frameworks.

The paper navigates RLHF's speculative future directions, highlighting alternatives such as direct preference optimization and synthetic preference data, while cautioning about the challenges these nascent methods might harbor. Additionally, the authors discuss issues such as the stability of RLHF-trained LLMs and emphasize the necessity for understanding societal impacts as they suggest solutions like red-teaming of reward models for safety assurance.

In conclusion, this paper advocates for a nuanced understanding of RLHF systems, proposing comprehensive evaluations and discussions around the implicit assumptions within current deployments of reward models. By critically examining RLHF from its intellectual roots to contemporary practices, the authors provide valuable insights, promoting responsible and technically sound advancements in human-centered AI systems. This substantial contribution could lead to better-informed policy and development decisions, ensuring the ethical deployment of AI technologies while better aligning models with genuine human values.