The Repeated-Stimulus Confound in Electroencephalography

Fuente: arXiv
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Main Authors: Kilgallen, Jack A., Pearlmutter, Barak A., Siskind, Jeffrey Mark
Format: Preprint
Published: 2025
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_version_ 1866918109961519104
author Kilgallen, Jack A.
Pearlmutter, Barak A.
Siskind, Jeffrey Mark
author_facet Kilgallen, Jack A.
Pearlmutter, Barak A.
Siskind, Jeffrey Mark
contents In neural-decoding studies, recordings of participants' responses to stimuli are used to train models. In recent years, there has been an explosion of publications detailing applications of innovations from deep-learning research to neural-decoding studies. The data-hungry models used in these experiments have resulted in a demand for increasingly large datasets. Consequently, in some studies, the same stimuli are presented multiple times to each participant to increase the number of trials available for use in model training. However, when a decoding model is trained and subsequently evaluated on responses to the same stimuli, stimulus identity becomes a confounder for accuracy. We term this the repeated-stimulus confound. We identify a susceptible dataset, and 16 publications which report model performance based on evaluation procedures affected by the confound. We conducted experiments using models from the affected studies to investigate the likely extent to which results in the literature have been misreported. Our findings suggest that the decoding accuracies of these models were overestimated by between 4.46-7.42%. Our analysis also indicates that per 1% increase in accuracy under the confound, the magnitude of the overestimation increases by 0.26%. The confound not only results in optimistic estimates of decoding performance, but undermines the validity of several claims made within the affected publications. We conducted further experiments to investigate the implications of the confound in alternative contexts. We found that the same methodology used within the affected studies could also be used to justify an array of pseudoscientific claims, such as the existence of extrasensory perception.
format Preprint
id arxiv_https___arxiv_org_abs_2508_00531
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Repeated-Stimulus Confound in Electroencephalography
Kilgallen, Jack A.
Pearlmutter, Barak A.
Siskind, Jeffrey Mark
Neurons and Cognition
Computer Vision and Pattern Recognition
62K99, 68T05
In neural-decoding studies, recordings of participants' responses to stimuli are used to train models. In recent years, there has been an explosion of publications detailing applications of innovations from deep-learning research to neural-decoding studies. The data-hungry models used in these experiments have resulted in a demand for increasingly large datasets. Consequently, in some studies, the same stimuli are presented multiple times to each participant to increase the number of trials available for use in model training. However, when a decoding model is trained and subsequently evaluated on responses to the same stimuli, stimulus identity becomes a confounder for accuracy. We term this the repeated-stimulus confound. We identify a susceptible dataset, and 16 publications which report model performance based on evaluation procedures affected by the confound. We conducted experiments using models from the affected studies to investigate the likely extent to which results in the literature have been misreported. Our findings suggest that the decoding accuracies of these models were overestimated by between 4.46-7.42%. Our analysis also indicates that per 1% increase in accuracy under the confound, the magnitude of the overestimation increases by 0.26%. The confound not only results in optimistic estimates of decoding performance, but undermines the validity of several claims made within the affected publications. We conducted further experiments to investigate the implications of the confound in alternative contexts. We found that the same methodology used within the affected studies could also be used to justify an array of pseudoscientific claims, such as the existence of extrasensory perception.
title The Repeated-Stimulus Confound in Electroencephalography
topic Neurons and Cognition
Computer Vision and Pattern Recognition
62K99, 68T05
url https://arxiv.org/abs/2508.00531