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Dissociation between arithmetic relatedness and distance effects is modulated by task properties: an ERP study comparing explicit vs. implicit arithmetic processing.


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Authors

Avancini, Chiara 
Galfano, Giovanni 
Szűcs, Dénes 

Abstract

Event-related potential (ERP) studies have detected several characteristic consecutive amplitude modulations in both implicit and explicit mental arithmetic tasks. Implicit tasks typically focused on the arithmetic relatedness effect (in which performance is affected by semantic associations between numbers) while explicit tasks focused on the distance effect (in which performance is affected by the numerical difference of to-be-compared numbers). Both task types elicit morphologically similar ERP waves which were explained in functionally similar terms. However, to date, the relationship between these tasks has not been investigated explicitly and systematically. In order to fill this gap, here we examined whether ERP effects and their underlying cognitive processes in implicit and explicit mental arithmetic tasks differ from each other. The same group of participants performed both an implicit number-matching task (in which arithmetic knowledge is task-irrelevant) and an explicit arithmetic-verification task (in which arithmetic knowledge is task-relevant). 129-channel ERP data differed substantially between tasks. In the number-matching task, the arithmetic relatedness effect appeared as a negativity over left-frontal electrodes whereas the distance effect was more prominent over right centro-parietal electrodes. In the verification task, all probe types elicited similar N2b waves over right fronto-central electrodes and typical centro-parietal N400 effects over central electrodes. The distance effect appeared as an early-rising, long-lasting left parietal negativity. We suggest that ERP effects in the implicit task reflect access to semantic memory networks and to magnitude discrimination, respectively. In contrast, effects of expectation violation are more prominent in explicit tasks and may mask more delicate cognitive processes.

Description

Keywords

Arithmetic relatedness, Distance effect, ERPs, Magnitude representation, Mental arithmetic, Adult, Brain, Electroencephalography, Evoked Potentials, Female, Humans, Male, Mathematics, Problem Solving, Semantics, Young Adult

Journal Title

Biol Psychol

Conference Name

Journal ISSN

0301-0511
1873-6246

Volume Title

103

Publisher

Elsevier BV
Sponsorship
Medical Research Council (G0900643)
Medical Research Council (G0001354)
This research was supported in part by a grant from the University of Padova to Giovanni Galfano and by the UK Medical Research Council grant G90951 (DS).