Poster C120, Sunday, March 26, 5:00 – 7:00 pm, Pacific Concourse
The Influence of Visual Cues on Nonsymbolic Number Comparison and Their Relation to Math Competency
Eric Wilkey1, Jordan C. Barone1, Michele M. M. Mazzocco2, Stephan E. Vogel3, Gavin R. Price1; 1Peabody College, Vanderbilt University, 2Institute of Child Development, University of Minnesota, 3Institute of Psychology, University of Graz, Austria
Nonsymbolic numerical comparison tasks (whereby a participant judges which of two groups of objects is more numerous) are thought to index the efficiency of the neurocognitive systems supporting the perception of numerical magnitude. Further, behavioral studies show that performance on the task is significantly influenced by the degree of congruency between non-numeric visual parameters, such as surface area and object size, and the number of items. One theory posits that these non-numerical cues require participants to inhibit their visually-based response before making a quantity-based judgment. It is not clear to what extent neural activation patterns during nonsymbolic comparison are influenced by numerical magnitude processing versus inhibition of non-numeric visual cues. In order to investigate this issue, we used functional magnetic resonance imaging (fMRI) to compare the BOLD activation patterns of 38 twelfth-grade students during a nonsymbolic comparison task in which half the trials were size controlled (incongruent) and half were not (congruent). Results indicate that (1) activity in the bilateral superior parietal and anterior cingulate cortex increase parametrically with the difficulty of ratios being compared, (2) the parametric increase differs according to congruency condition in the right intraparietal sulcus (IPS) and inferior frontal gyrus, and (3) ratio-dependent activity correlates to math competency in a third, medial aspect of the right IPS. These results suggest that multiple parietal mechanisms are involved in the comparison of numerical magnitudes that differ according to visual task demands, and further, that a ratio-dependent increase in parietal activity is related math competency.
Topic Area: PERCEPTION & ACTION: Other