Projects

Skip to content Skip to main navigation
Teachers College, Columbia University
Printer-friendly Version
Teachers College, Columbia University Logo
Banner

Language and Cognition Lab

An EEG research study on how the brain processes numbers.

Research on numerical cognition with infants, children, adults, cross-cultural studies and animal studies converge on the conclusion that there are two distinct systems for the perception of numerical quantity: A small-number system (1~3) invoking parallel individuation, or “subitizing”, and a large-number system (4+) that is based on Weberian magnitude estimation. The present study employed high density EEG to investigate the neural basis of differentiation between small-number (1~3), and large-number (4~6) perception. During EEG data collection, participants were presented with dot pattern stimuli containing 1 to 6 dots of varying size. They were instructed to press a key when they detected a change in the number of dots presented and were rewarded for correctly detecting changes. ERP analyses were conducted over the left and right occipital-temporal-parietal junction. For the early ERP component (N1; 160~180 ms), we observed that there was separation of ERPs within the subitizing range (1~3) but not beyond (4~6). A second later positivity (P3) was found in Cz and neighboring electrodes, that was associated with change detection. Numerical changes were categorized as “within small” (1~2, 2~1, 2~3, 3~2), “within large” (4~5,5~4,5~6,6~5). Changes that crossed the small to large boundary were labeled “small-to-large” and “large-to- small”. The P3 was observed for all change categories except for “within large.” These data, taken together, suggest a neural basis for the differentiation of small vs. large number perception at early stages of processing, and a later stage that involves more semantic numerical processing that is employed in change detection task.


Contact: pgordon@tc.edu


Principal Investigator: Peter Gordon

Research Assistants: Sungbong Kim, Mary Llenell Paz, Erin (Reddick) Kirby, Michael Small, Jean Tang