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Finding the SNARC instead of hunting it: A 20*20 monte carlo investigation

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journal contribution
posted on 23.04.2020, 12:26 authored by Krzysztof CiporaKrzysztof Cipora, G Wood
© 2017 Cipora and Wood. The Spatial Numerical Association of Response Codes (SNARC) effect describes a stimulus-response association of left with small magnitude and right with large magnitude. Usually, it is estimated by means of regression slopes, where the independent variable only has a limited number of levels. Inspection of the literature reveals that it is not difficult to detect a SNARC effect within a group, but it has been quite unusual to find group differences. Is the SNARC effect as it is usually estimated using regression slopes largely insensitive to group differences, and are there design parameters necessary to increase sensitivity in group comparison analyses? Using numerical simulations, we provide evidence that both sample size and the number of stimulus repetitions, as well as intra-individual variability, contribute in a substantial way to the probability of detecting an existing SNARC effect. Our results show that the adequate choice of either sample size or number of repetitions per experimental cell does not fully compensate for a poor choice of the other parameter. Moreover, repeated failures to find significant group differences in the SNARC effect can be explained by insufficient power. Fortunately, increasing the number of repetitions to about 20 and testing at least 20 participants provides in most cases sufficient sensitivity to reliably detect the SNARC effect as well as group differences. Power plots are provided, which may help to improve both the economy and sensitivity of experimental design in future SNARC experiments, or, more generally when regression slopes are estimated intra-individually.

Funding

Deutsche Forschungsgemeinschaft (German Research Foundation; DFG NU 265/3-1) on “Linguistic Influences on Numerical Cognition: A cross-cultural investigation using natural specificities of Polish and German languages.”

History

School

  • Science

Department

  • Mathematical Sciences

Published in

Frontiers in Psychology

Volume

8

Issue

JUL

Pages

1194

Publisher

FRONTIERS MEDIA SA

Version

VoR (Version of Record)

Rights holder

© The authors

Publisher statement

This is an Open Access Article. It is published by Frontiers Media under the Creative Commons Attribution 4.0 Unported Licence (CC BY). Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

Acceptance date

30/06/2017

Publication date

2017-07-18

Copyright date

2017

ISSN

1664-1078

eISSN

1664-1078

Language

en

Depositor

Dr Krzysztof Cipora. Deposit date: 21 April 2020

Article number

ARTN 1194