October 29, 2018 - Professor Ian Lyons has published a new paper in the Journal of Cognitive Neuroscience.
Multiplication is thought to be primarily solved via direct retrieval from memory. However, two of the main factors in the retrieval of multiplication facts – problem-size and interference – have proven difficult to disentangle. Here we managed to do so using a novel means of analyzing fMRI data during multiplication fact-retrieval in healthy adults. Both behavioral and fMRI results showed that both problem-size and interference explained separate unique portions of multiplication variance, but with significantly stronger contribution from problem-size. Whole-brain fMRI results showed highly overlapping brain areas for both problem-size and interference in a large network of frontal, parietal and subcortical brain areas. Subsequent novel analysis within these regions revealed problem-size to be the stronger and more consistent unique modulating factor in overlapping regions as well as those that appeared to respond only to problem-size or interference at the whole-brain level, thus underscoring the need to look beyond anatomical overlap using arbitrary thresholds. Together, our results show that problem-size, relative to interference, tends to be the more dominant factor in driving behavioral and neural responses during multiplication fact retrieval in adults. Nevertheless, unique contributions of both factors demonstrate the importance of considering the overlapping and unique contributions of each in explaining the cognitive and neural bases of mental multiplication. These results show how behavioral and neuroimaging data can be used in concert to advance our understanding of a ubiquitous cognitive phenomenon in modern life – retrieval of basic multiplication facts.
tiberghien K, Sahan MI, De Smedt B, Fias W, Lyons IM (in press) Disentangling neural sources of problem-size and interference effects in multiplication. Journal of Cognitive Neuroscience.