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Neurobehavioral Dynamics of Numerical Change: Directional and Numerical Distance Processing

Poster Session F - Tuesday, March 10, 2026, 8:00 – 10:00 am PDT, Fairview/Kitsilano Ballroom

Vanessa Rhee¹ (), Zhiyi Chen¹, Mischa Gushiken¹, Kiren Bakhru¹, Hanyi Xu³, Nick Bisbee², Yuexin Li¹, Sadra Gerami¹, Jean Ee Tang¹, Peter Gordon¹; ¹Teachers College, Columbia University, ²Johns Hopkins University, ³Graduate School of Arts and Sciences, Columbia University

This study reanalyzes spatiotemporal and behavioral data from a numerical change detection task, where arrays of 1–6 dots were shown in habituation and change trials using a 128-channel EEG system. Twenty-four adults viewed sequential dot arrays and pressed a key upon detecting numerical changes; reaction time (RT) and accuracy were recorded. Both change and no-change trials were included for comparison. The original goal was to examine whether N1 deflections for Small (1–3) versus Large (4–6) numerosities in the Parietal-Occipital-Temporal (POT) montage follow the same scaling pattern reported by Hyde and Spelke (2009). Differences between small and large set sizes were consistent with prior findings (Tang et al., 2025). We extended the analysis to include No-Change (baseline) and Change conditions, numerical distance (1, 2, or 3), and change direction (Increasing vs. Decreasing). Unlike Hyde and Spelke’s passive task, participants in our study actively responded to numerical changes. RTs decreased with larger numerical distances, and accuracy was higher for Decreasing trials and greater distances. Because numerosity changes were actively monitored, we also analyzed midline frontal (Fz) activity to assess Mismatch Negativity (MMN) as a neural index of change detection. MMN was measured at 100–120 ms post-stimulus, while P1 (80–120 ms) and N1 (125–200 ms) were analyzed over bilateral POT regions. Stronger MMN amplitudes were found for Decreasing versus Increasing changes, scaling with numerical distance. MMN amplitude increased with greater differences, and latency was shorter for Increasing trials. P1–N1 differences in POT regions similarly grew with numerical distance in both directions.

Topic Area: PERCEPTION & ACTION: Vision