Computational underpinnings of cognitive effortful performance in short timescales

Despite recent advancements, the mechanisms underlying the decline in cognitive performance with sustained effort remain unclear. In four experiments (total N ≈ 200), participants engaged in a sustained attention task comprising four blocks of 50 or 200 trials presented in a randomized order. We found that performance declined over both extremely brief and longer bouts of performance, as evidenced by a reduction in correct responses per second. Computational modeling revealed that this decline is driven by a decreasing allocation of cognitive resources to the task. These findings align with theoretical accounts positing that cognitive fatigue reflects adjustments in resource allocation, rather than resource depletion.