Beyond Suboptimality: Resource-Rationality and Task Demands Shape the Complexity of Perceptual Representations

Early theories of perception as probabilistic inference propose that uncertainty about the interpretation of sensory input is represented as a probability distribution over many interpretations -- a relatively complex representation. However, critics argue that persistent demonstrations of suboptimal perceptual decision-making indicate limits in representational complexity. We contend that suboptimality arises not from genuine limits, but participants' resource-rational adaptations to task demands. For example, when tasks are solvable with minimal attention to stimuli, participants may neglect information needed for complex representations, relying instead on simpler ones that engender suboptimality. Across three experiments, we progressively reduced the efficacy of resource-rational strategies on a carefully controlled decision task. Model fits favored simple representations when resource-rational strategies were effective, and favored complex representations when ineffective, suggesting that perceptual representations can be simple or complex depending on task demands. We conclude that resource-rationality is an epistemic constraint for experimental design and essential to a complete theory of perception.