Didino, D. 1, 2 , Vespignani, F. 1 & Lombardi, L. 1
1 Dipartimento di Scienze della Cognizione e della Formazione, University of Trento, Trento, Italy
2 Institute of Cognitive Neuroscience, University College of London, London, United Kingdom
In order to better understand the internal organization of the memory network that encodes arithmetic facts we studied the effect of operand-order on the speed of solution of one-digit multiplications. 24 Italian participants were asked to report the result of the operations. The analysis of the RTs showed an interaction between the size of the problem (both operands larger than 5, e.g. 7x8; one larger and the other smaller than 5, 3x7; and both smaller than 5, 3x4) and the order of the operands (first larger, 8x4; and second larger, 4x8). When both operands were larger than 5, the problems with the second operand larger were solved faster, e.g. RT(7x8)<RT(8x7). When one operand was larger and the other was smaller than 5, the problems with the first operand larger were solved faster, RT(7x3)<RT(3x7). Similar results were obtained in a second experiment in English (24 participants). We exclude the interaction is due to the operand-order during the acquisition of the multiplication table, given that the two languages differ in the order of operands during the table learning. The results can be rather explained by a model of retrieval with an asymmetric right skewed activation of multiples around ties.