Schedule of Events | Symposia

Neural and autonomic correlates of working memory overload

Poster Session B - Sunday, March 30, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Yuri G. Pavlov¹ (pavlovug@gmail.com), Dauren Kasanov², Alexander Kotyusov², Alexandra Kosachenko²; ¹University of Alabama at Birmingham, ²Ural Federal University, Ekaterinburg, Russian Federation

Objective methods for detecting cognitive overload are crucial for understanding and managing working memory demands. This study explored the effects of exceeding individual working memory capacity (digit span) on psychophysiological indicators, including frontal midline theta, posterior alpha, and pupil size. A total of 137 participants performed a digit span task involving serial presentation and recall of digits, while 64-channel EEG and pupillometry data were recorded. Each trial presented a sequence of visually displayed digits, with sequence length tailored to either match the individual’s digit span (≥70% correct recall, “span” condition) or exceed it by one digit (“overload” condition). The overload condition was perceived as more challenging, as evidenced by higher NASA-TLX subjective cognitive load ratings and reduced behavioral accuracy. While alpha power did not significantly differentiate between the conditions, theta power exhibited a stronger and more stable increase during the latter half of the overload trials. In contrast, pupillometry revealed distinct dynamics, with smaller pupil sizes observed in the several digits preceding the last one in the overloading sequences. These findings suggest that theta power and pupil size are robust indicators of cognitive overload, though their temporal patterns and direction of the effect differ. Alpha activity, however, appears to reflect cognitive overload less directly, manifesting as a stabilization rather than an immediate surge or drop in the spectral power.

Topic Area: EXECUTIVE PROCESSES: Working memory