Judging orientation does not elicit the Spatial-Numerical Association of Response Codes: Testing the Neural Overlap Hypothesis
Abstract
According to the neural overlap hypothesis (Fias et al., 2001), numerical magnitude may influence performance in a non-semantic task when the processing of task-relevant and task-irrelevant information recruits overlapping neural structures. Specifically, because number and orientation processing both engage parietal regions, the account predicts a SNARC effect during orientation judgments, whereas effects should be weaker in tasks with less parietal involvement, such as colour judgments. However, only a few studies have attempted to replicate the original findings. Here, we conducted a large-sample replication of the line orientation task introduced by Fias et al. (2001, Experiment 4) and included letters as a complementary condition. Across two experiments, conducted online and in the laboratory, we consistently failed to detect a SNARC effect for numbers or a SNARC-like effect for letters. A cumulative analysis likewise provided no evidence for either association. These findings fail to replicate a key result supporting the neural overlap hypothesis and suggest that shared parietal processing may not give rise to spatial-numerical associations as robustly as previously assumed.
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BibTeX
@misc{prpic2026judging,
title = {{Judging orientation does not elicit the Spatial-Numerical Association of Response Codes: Testing the Neural Overlap Hypothesis}},
author = {Valter Prpic and Stefano Pileggi and Alberto Mariconda and Serena Mingolo and MAURO MURGIA},
howpublished = {PsyArXiv},
year = {2026},
month = oct,
doi = {10.31234/osf.io/fp69k_v2},
url = {https://osf.io/preprints/psyarxiv/fp69k_v2/},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Judging orientation does not elicit the Spatial-Numerical Association of Response Codes: Testing the Neural Overlap Hypothesis
AU - Valter Prpic
AU - Stefano Pileggi
AU - Alberto Mariconda
AU - Serena Mingolo
AU - MAURO MURGIA
PY - 2026
DA - 2026/10/14
PB - PsyArXiv
DO - 10.31234/osf.io/fp69k_v2
UR - https://osf.io/preprints/psyarxiv/fp69k_v2/
AB - According to the neural overlap hypothesis (Fias et al., 2001), numerical magnitude may influence performance in a non-semantic task when the processing of task-relevant and task-irrelevant information recruits overlapping neural structures. Specifically, because number and orientation processing both engage parietal regions, the account predicts a SNARC effect during orientation judgments, whereas effects should be weaker in tasks with less parietal involvement, such as colour judgments. However, only a few studies have attempted to replicate the original findings. Here, we conducted a large-sample replication of the line orientation task introduced by Fias et al. (2001, Experiment 4) and included letters as a complementary condition. Across two experiments, conducted online and in the laboratory, we consistently failed to detect a SNARC effect for numbers or a SNARC-like effect for letters. A cumulative analysis likewise provided no evidence for either association. These findings fail to replicate a key result supporting the neural overlap hypothesis and suggest that shared parietal processing may not give rise to spatial-numerical associations as robustly as previously assumed.
ER -