Finding the SNARC Instead of Hunting It: A 20∗20 Monte Carlo Investigation
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. Inspec...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2017-07-01
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| Series: | Frontiers in Psychology |
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| Online Access: | http://journal.frontiersin.org/article/10.3389/fpsyg.2017.01194/full |
| _version_ | 1811302881446330368 |
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| author | Krzysztof Cipora Guilherme Wood |
| author_facet | Krzysztof Cipora Guilherme Wood |
| author_sort | Krzysztof Cipora |
| collection | DOAJ |
| description | 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. |
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| format | Article |
| id | doaj.art-bad8bbeb3dfe4702a48d212495c11cee |
| institution | Directory Open Access Journal |
| issn | 1664-1078 |
| language | English |
| last_indexed | 2024-04-13T07:36:08Z |
| publishDate | 2017-07-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Psychology |
| spelling | doaj.art-bad8bbeb3dfe4702a48d212495c11cee2022-12-22T02:56:07ZengFrontiers Media S.A.Frontiers in Psychology1664-10782017-07-01810.3389/fpsyg.2017.01194243273Finding the SNARC Instead of Hunting It: A 20∗20 Monte Carlo InvestigationKrzysztof Cipora0Guilherme Wood1Department of Psychology, University of TübingenTübingen, GermanyInstitute of Psychology, Karl-Franzens-University of GrazGraz, AustriaThe 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.http://journal.frontiersin.org/article/10.3389/fpsyg.2017.01194/fullSNARC effectMonte Carlo simulationspower analysisANOVARegression Analysis |
| spellingShingle | Krzysztof Cipora Guilherme Wood Finding the SNARC Instead of Hunting It: A 20∗20 Monte Carlo Investigation Frontiers in Psychology SNARC effect Monte Carlo simulations power analysis ANOVA Regression Analysis |
| title | Finding the SNARC Instead of Hunting It: A 20∗20 Monte Carlo Investigation |
| title_full | Finding the SNARC Instead of Hunting It: A 20∗20 Monte Carlo Investigation |
| title_fullStr | Finding the SNARC Instead of Hunting It: A 20∗20 Monte Carlo Investigation |
| title_full_unstemmed | Finding the SNARC Instead of Hunting It: A 20∗20 Monte Carlo Investigation |
| title_short | Finding the SNARC Instead of Hunting It: A 20∗20 Monte Carlo Investigation |
| title_sort | finding the snarc instead of hunting it a 20∗20 monte carlo investigation |
| topic | SNARC effect Monte Carlo simulations power analysis ANOVA Regression Analysis |
| url | http://journal.frontiersin.org/article/10.3389/fpsyg.2017.01194/full |
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