How Proportional Representation Can Shape Artificial Intelligence

Abstract Proportional representation is a foundational principle in social choice theory, ensuring that groups influence collective decisions in proportion to their size. While it has traditionally been studied in the context of political elections, recent work in computational social choice has broadened its scope to a variety of voting frameworks. This article showcases how proportional representation can be formalized and applied beyond these frameworks, spotlighting AI domains where it naturally takes shape. In particular, we focus on two such domains: clustering and AI alignment. In clustering, proportionality ensures that sufficiently large and cohesive groups of data points or agents are adequately represented in the selection of cluster centers or group assignments, to both centroid‐based and noncentroid‐based paradigms. In AI alignment, particularly in reinforcement learning from human feedback (RLHF), proportionality provides a principled framework for aggregating heterogeneous preferences by designing committees of reward functions that reflect annotators' viewpoints in proportion to their prevalence. We also discuss additional promising applications, including client selection in federated learning and forming committees of pre‐trained models in meta‐learning, and argue that incorporating proportional representation into AI systems provides a mathematically rigorous foundation for aligning algorithmic outcomes with the breadth of human viewpoints.