Re-Thinking the Number Sense: The Perceptual Interdependence Account

Questions about whether humans possess a dedicated “number sense” have shaped theories of numerical cognition for decades. The classic perspective proposes that numerosity is extracted directly from the environment and encoded independently of other magnitudes such as area, density, or duration. In this chapter, we review accumulating evidence that challenges this independence—and, thus, the supposed abstract nature of numerosity representations. We introduce a Perceptual Interdependence account, in which numerical and non-numerical magnitudes are jointly encoded within perception, with interactions emerging early in processing. We draw on developmental, comparative, and computational research showing that number primacy (i.e., its privileged status over non-numerical magnitudes) is neither the developmental nor evolutionary default. Instead, the relative weighting of number versus other magnitudes varies with experience, context, and attentional demands. We argue that attention plays a key role in selectively tuning integrated magnitude representations for decision-making, offering a bridge between perceptual representations of numerosity and later-emerging symbolic number concepts. This perspective reframes non-symbolic number as a perceptual construct—one that emerges from integrated magnitude processing rather than a standalone core system.