CiNet Monthly Seminar

August 3 (Mon.), 2026
16:00-17:00 (JST)
at the Conference Room in the CiNet bldg.

Talk title: The emergence of number sense in the brain

Joonkoo Park
Associate Professor
Department of Psychological and Brain Sciences, University of Massachusetts Amherst
USA

Host : Sofia Nagisa, Masamichi Hayashi

Abstract:
Perceiving numerosity (the number of items in a collection) is a fundamental ability for all animals. However, this poses a significant theoretical challenge from a neurocomputational perspective, as it is unclear how a discrete value is encoded in the brain when neural signals are inherently continuous. From a series of psychophysical, neural, and computational modeling studies, I propose algorithmic-level mechanisms for the sensory representation of numerosity. The core of the proposal is that numerosity perception emerges as a byproduct of canonical perceptual principles such as center-surround receptive field properties, divisive normalization, and coarse-to-fine processing. According to this view, number sense does not emerge from the representation of numbers but rather from the representation of normalized local contrast. These findings call for a clear distinction between percepts and concepts of number and further investigations about the neural processes beyond the initial sensory representational stage needed to construct the conceptual content of number.