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arXivSource publication:

GRID disentangles a general reward from heterogeneous demonstrators, enabling generalist pretraining that outperforms standard learning-from-demonstration baselines

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Synopsis

The work introduces General Reward Inference and Disentanglement (GRID), a social learning method that uses an information bottleneck to decompose each agent's reward function into a general reward shared across all agents and specific rewards capturing individual preferences, so that training solely on the general reward yields a generalist agent internalizing universal environmental competencies such as safety and basic task proficiency; experiments on a synthetic basis function decomposition, multi-agent Craftax, MuJoCo Gym continuous control, and the Highway-Env driving simulator confirm semantically meaningful reward disentanglement, outperformance of standard learning-from-demonstration baselines, and more efficient and stable specialization.

Source-provided article image: Do as the Romans Do: Learning Universal Behaviors from Heterogeneous Agents
Figure 2 ·

Figure 2: The model architecture of GRID. The summed outputs of the general and specific reward models yield the total reward. ℒ compression \mathcal{L}_{\text{compression}} and ℒ identity \mathcal{L}_{\text{identity}} form the information bottleneck while ℒ reconstruction \mathcal{L}_{\text{reconstruction}} helps predict the total reward. Losses are jointly optimized.

arXiv

Interpretation

GRID decomposes each demonstrator's reward function into a general reward, capturing behaviors shared across all agents, and specific rewards, capturing individual preferences and objectives. Prior learning from demonstration typically treats the behavioral signals of a heterogeneous population together, whereas this work explicitly separates reward structure into shared and individual components, making it possible to determine which behaviors are worth imitating. The summary states the decomposition is achieved through an information bottleneck and that a synthetic basis function decomposition experiment confirms the reward structure is disentangled in a semantically meaningful way.

Training exclusively on the general reward constitutes a generalist pretraining paradigm, yielding a generalist agent that internalizes universal environmental competencies such as safety and basic task proficiency without the mode-averaging bias of standard learning from demonstration. This offers a pretraining path distinct from directly imitating heterogeneous demonstrations: first extract behaviors shared across agents, then adapt downstream, rather than averaging over conflicting signals. The summary contrasts mode-averaging bias as affecting standard learning from demonstration techniques, while general-reward training is reported to avoid it.

The generalist serves as a strong prior for fine-tuning to downstream tasks, including preferences unseen during training, and enables more efficient and stable specialization. The product of generalist pretraining is positioned as a transferable prior rather than a policy serving only the goals seen during training, linking universal behavior learning to subsequent individualized adaptation. The summary reports that on MuJoCo Gym continuous control and the Highway-Env autonomous driving simulator, GRID outperforms standard learning-from-demonstration baselines and yields more efficient and stable specialization.

GRID is validated across a synthetic basis function decomposition, multi-agent Craftax, continuous control tasks, and an autonomous driving simulator. Validation spans controlled synthetic decomposition, a multi-agent environment, and continuous control and driving simulation, indicating the method is not confined to a single task form. The summary lists these four experimental settings and states they confirm reward structure disentanglement, baseline outperformance, and efficient stable specialization.

Perspective

The work targets extracting universal behaviors from a heterogeneous population of demonstrators, suited to settings with multiple demonstrators pursuing different goals where a transferable general prior is desired, such as multi-agent environments, continuous control, and driving simulation. Its generalist is positioned as a strong prior for downstream fine-tuning, so the direct beneficiaries are researchers and practitioners who need to specialize on top of heterogeneous demonstrations. The validation described in the summary covers a synthetic basis function decomposition, multi-agent Craftax, MuJoCo Gym, and Highway-Env, indicating the conclusions hold primarily under these experimental conditions.

At the summary level, no concrete metrics, sample sizes, or statistical significance are given for the experiments, so the magnitude of general-reward training's advantage over baselines remains unclear. The specific form of the information bottleneck, the criteria separating general from specific rewards, and how mode-averaging bias is measured all need confirmation in the full text. The generalist's adaptation to preferences unseen during training is stated only in general terms, leaving its robustness and scope an open question worth watching. In addition, this reading is summary-scoped and excludes figures and appendices, so these judgments may change with the complete content.

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