https://doi.org/10.1140/epjs/s11734-026-02366-z
Regular Article
Riemannian geometry of eye-movement covariance matrices during a prolonged working memory task
Plekhanov Russian University of Economics, 36 Stremyanny Lane, Moscow, Russia
a
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Received:
9
April
2026
Accepted:
27
April
2026
Published online:
8
May
2026
Abstract
Eye movements reflect cognitive processing during working memory performance. However, it remains unclear how prolonged task execution and increasing fatigue affect the integrated organization of oculomotor behavior under different memory demands. In this study, we analyzed covariance patterns of trial-wise eye-movement features during a prolonged Sternberg task using a Riemannian geometry framework. To quantify the differentiation between oculomotor states associated with different levels of task demand, we introduced the Oculomotor Differentiation Index (ODI). The results showed that oculomotor states corresponding to different working memory demands were clearly differentiated during the earlier stages of the experiment, but this differentiation progressively weakened and was no longer evident at the final stage. In addition, higher subjective fatigue was associated with lower differentiation between demand-related oculomotor states. These findings suggest that increasing fatigue is associated with a weakening of task-specific oculomotor tuning, so that eye-movement behavior becomes less selectively organized with respect to cognitive demand. The study also shows that a covariance-based manifold approach can capture integrated changes in oculomotor state organization that are not evident from isolated eye-movement measures alone.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
