Quantifying variability in attentional shifts during target switching.

Steady-state evoked potentials research has provided significant insights into temporal dynamics of attentional processes. While these studies focused primarily on group-level inspection, there is a need for further research employing methodological approaches that enable the examination of individual-level variability, often linked to various cognitive and clinical outcomes. In the present study (n = 29), we aimed to measure and discern attentional shift processes, examining both group and individual subject dynamics. We utilized electroencephalographic frequency tagging to examine attentional engagement, disengagement, and reengagement while participants switched focus between four flickering stimuli. Analysis of ssVEPs revealed significant changes in amplitude between attentional conditions. Group-level results indicated an increase in activity during engagement with the first target, followed by a decrease upon disengagement, while reengagement with the second target showed a corresponding increase in activity occurring on average 110 ms prior to disengagement. Distinct individual patterns emerged, with participants showing either disengagement, reengagement, both, or no shifts. Notably, the timing and order of these attentional shifts varied considerably. These findings demonstrate the ability of this approach to quantify attentional shifts on both group and individual-level, providing a foundation for further research into individual differences in attentional control, with implications for understanding adaptive and maladaptive psychological functioning.