Do numbers make us handy? Behavioral and electrophysiological evidence for number-hand congruency effect

Saied Sabaghypour; Hassan Sabouri Moghaddam; Farhad Farkhondeh Tale Navi; Mohammad Ali Nazari; Mojtaba Soltanlou

doi:10.1016/j.actpsy.2023.103841

Do numbers make us handy? Behavioral and electrophysiological evidence for number-hand congruency effect

Acta Psychol (Amst). 2023 Mar:233:103841. doi: 10.1016/j.actpsy.2023.103841. Epub 2023 Jan 27.

Authors

Saied Sabaghypour¹, Hassan Sabouri Moghaddam², Farhad Farkhondeh Tale Navi², Mohammad Ali Nazari³, Mojtaba Soltanlou⁴

Affiliations

¹ Department of Cognitive Neuroscience, Faculty of Education and Psychology, University of Tabriz, Tabriz, Iran. Electronic address: saied.sabaghy@gmail.com.
² Department of Cognitive Neuroscience, Faculty of Education and Psychology, University of Tabriz, Tabriz, Iran.
³ Department of Neuroscience, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran.
⁴ Department of Cognitive Neuroscience, Faculty of Education and Psychology, University of Tabriz, Tabriz, Iran; School of Psychology, University of Surrey, Guildford, UK.

PMID: 36709688
DOI: 10.1016/j.actpsy.2023.103841

Abstract

Finger counting facilitates numerical representations and mathematical processing. The current study investigated the association between finger counting habits and number processing by employing behavioral and electrophysiological measures. We explored whether small and large numerical primes influence the recognition of embodied target hand stimuli. Twenty-four right-handed participants that were grouped into right-starters (n = 13) and left-starters (n = 11) for finger counting performed a hand recognition task that consisted of numerical magnitudes as prime and hand recognition as targets. Based on the finger counting habits, congruent (i.e., left-starters: small number/left hand or large number/right hand; right-starters: small number/right hand or large number/left hand) and incongruent (i.e., left-starters: large number/left hand or small number/right hand; right-starters: large number/right hand or small number/left hand) conditions were presented to the participants. The participants were required to indicate whether the targets were left or right hand by simply pressing the left or the right key, respectively. Results indicated faster reaction times (RTs) for congruent as opposed to incongruent trials for all participants. The mean amplitude of the centro-parietal P300 component was significantly increased for the incongruent compared to congruent condition, indicating increased mental effort. Also, analysis of the latency of the P300 in terms of congruency effect in all participants revealed significant results. These combined results provide behavioral and electrophysiological evidence indicating the embodied nature of numbers. The results are interpreted in light of the general findings related to the P300 component. This research supports the association of number-hand representations and corroborates the idea of embodied numerosity.

Keywords: Congruency effect; ERP; Event-related potentials; Finger counting habits; Hand recognition; Numerical processing.

MeSH terms

Fingers*
Habits*
Humans
Mathematics
Reaction Time / physiology
Recognition, Psychology