Neural evidence for an abstract sense of number in humans at birth

One of the most astonishing abilities documented in human newborns is that they can abstract numerosity – the number of items in sets - across sensory modalities. Its underlying neural mechanisms remain unknown. Using high-density EEG and a frequency-tagging paradigm, we measured neural entrainment to periodically presented visual arrays that were either numerically congruent or incongruent with previously familiarized and concurrently presented auditory sequences in 21 newborns (0–3 days old). The amplitude of neural entrainment to the visual arrays provided a robust index of cross-modal numerical congruency: it was significantly reduced for numerically congruent relative to incongruent stimuli, consistent with a cross-modal numerosity repetition-suppression mechanism. These findings identify a candidate neural mechanism supporting newborns’ ability to encode numerosity in an abstract supramodal format, and reinforce the view that number constitutes a foundational dimension of human perception since birth.