Attention to number: The convergence of numerical magnitude processing, attention, and mathematics in the inferior frontal gyrus

Abstract

Research indicates that the neurocognitive system representing nonsymbolic numerical magnitudes is foundational for the development of mathematical competence. However, recent studies found that the most common task used to measure numerical acuity, the nonsymbolic number comparison task, is heavily influenced by non-numerical visual parameters of stimuli that increase executive function demands. Further, this influence may be a confound invalidating theoretical accounts of the relation between number comparison performance and mathematical competence. Instead of acuity, the relation may depend on attention to number, or one’s ability to attend to numerical information in the face of competing, non-numerical cues. The current study investigated this issue by measuring neural activity associated with numerical magnitude processing acuity, domain-general attention, and selective attention to number via functional magnetic resonance imaging (fMRI) while children 8–11 years old completed a nonsymbolic number comparison task and a flanker task. Results showed that activation in the right inferior frontal gyrus during incongruent versus congruent trials of the comparison task, our construct for attention to number, predicted mathematics achievement after controlling for verbal IQ, flanker accuracy rate, and the neural congruency effect from the flanker task. In contrast, activity in frontal and parietal regions responding to differences in difficulty of numerical comparisons, our construct for magnitude processing, did not correlate with achievement. Together, these findings suggest a need to reframe existing models of the relation between number processing and math competence to include the interaction between attention and use of numerical information, or in other words “attention to number”.

Challenging the neurobiological link between number sense and symbolic numerical abilities

“…The flanker task is well matched for the inhibition effects brought on by irrelevant visual cues (conflicting direction of arrows) but in a nonnumerical domain. After running the same correlation between the congruency effect in the number comparison task and math as before, but controlling for inhibitory control both behaviorally and with a neural contrast from the flanker task, the correlation with math remained . This correlation indicates that the numerical nature of the number comparison task is an important factor for the relation to math over and above domain‐general attentional mechanisms.…”

“…In contrast to the significance of IFG activity, no relation was found between IPS activity and math achievement . This is an important missing element because previous literature has focused on the link between parietal function, number perception, and math.…”

“…And, in children, individual differences in this congruency effect during number comparison right IFG correlated with mathematics achievement, with a smaller congruency effect relating to better math achievement (Fig. ) . In other words, the numerical congruency effect, captured as activity in the IFG during the number comparison task, relates to better math scores.…”

“…To date, four studies have directly investigated the issue of congruency during the nonsymbolic number comparison task with neuroimaging: two studies with adults, one with adolescents, and one with children . All four studies did show a number of regions that exhibited an effect of congruency, where incongruent trials of the same numerical ratio elicited a greater response than congruent trials, indicating the engagement of mechanisms used to resolve conflicting visual congruency.…”

“…Results from Wilkey and Price of the relation between the numerical congruency effect and math achievement . (Top) Results from double subtraction contrast of congruency effect in number comparison task > congruency effect in flanker task (cluster corrected at P < 0.05, uncorrected P < 0.005).…”