Measuring conscious tactile perception without report: pupil, blink, and microsaccade signatures of a tactile no-report paradigm
- 1Yale School of Medicine
Abstract
Conscious perception is often inferred from behavioral reports, which conflate awareness-related neural signals with the motor and decision processes required to respond. No-report paradigms address this by using spontaneous physiological signals, such as eye movements, to infer perception. Although our group developed a no-report visual paradigm, we had not applied this approach to touch. We developed a no-report tactile paradigm using the Galileo stimulation system to deliver pneumatic air puffs to non-thumb fingers on both hands while tracking eye movements. Participants reported sensations from the Report hand while receiving threshold-level puffs on both hands; eye metrics were used to infer perception in the No-Report hand. Perceived threshold-level stimuli elicited greater pupil dilation and more post-stimulus blinking than identical unperceived stimuli, with effects lasting 1 - 2 seconds. Microsaccade rate decreased after stimulus onset, but this suppression did not reach statistical significance. A stacked support vector machine trained on the Report eye-tracking measures was applied to classify No-Report trials and successfully separated [Predicted] Perceived from [Predicted] Not Perceived trials (AUC = .92; cross-validated accuracy = 72%; sensitivity = 90% at 80% specificity; label-permutation p < .001). These findings show that eye tracking can detect conscious tactile perception without overt responses and offer a noninvasive, scalable approach for studying tactile perception in patients with self-reported disabilities, including comatose or intubated patients.
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BibTeX
@misc{sharma2026measuring,
title = {{Measuring conscious tactile perception without report: pupil, blink, and microsaccade signatures of a tactile no-report paradigm}},
author = {A. A. Sharma and R. Senjalia and A. Woodworth and D. Jin and S. Aerts and D. Cormier and A. Khalaf and H. Blumenfeld},
howpublished = {bioRxiv},
year = {2026},
month = oct,
doi = {10.64898/2026.10.29.762884},
url = {https://www.biorxiv.org/content/10.64898/2026.10.29.762884v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Measuring conscious tactile perception without report: pupil, blink, and microsaccade signatures of a tactile no-report paradigm
AU - A. A. Sharma
AU - R. Senjalia
AU - A. Woodworth
AU - D. Jin
AU - S. Aerts
AU - D. Cormier
AU - A. Khalaf
AU - H. Blumenfeld
PY - 2026
DA - 2026/10/29
PB - bioRxiv
DO - 10.64898/2026.10.29.762884
UR - https://www.biorxiv.org/content/10.64898/2026.10.29.762884v1
AB - Conscious perception is often inferred from behavioral reports, which conflate awareness-related neural signals with the motor and decision processes required to respond. No-report paradigms address this by using spontaneous physiological signals, such as eye movements, to infer perception. Although our group developed a no-report visual paradigm, we had not applied this approach to touch. We developed a no-report tactile paradigm using the Galileo stimulation system to deliver pneumatic air puffs to non-thumb fingers on both hands while tracking eye movements. Participants reported sensations from the Report hand while receiving threshold-level puffs on both hands; eye metrics were used to infer perception in the No-Report hand. Perceived threshold-level stimuli elicited greater pupil dilation and more post-stimulus blinking than identical unperceived stimuli, with effects lasting 1 - 2 seconds. Microsaccade rate decreased after stimulus onset, but this suppression did not reach statistical significance. A stacked support vector machine trained on the Report eye-tracking measures was applied to classify No-Report trials and successfully separated [Predicted] Perceived from [Predicted] Not Perceived trials (AUC = .92; cross-validated accuracy = 72%; sensitivity = 90% at 80% specificity; label-permutation p < .001). These findings show that eye tracking can detect conscious tactile perception without overt responses and offer a noninvasive, scalable approach for studying tactile perception in patients with self-reported disabilities, including comatose or intubated patients.
SN - 2692-8205
ER -