From internal timing to external clock-checking: the impact of ego depletion on dual-path attention in TBPM and the precise remediation by reminders.

Ego depletion refers to a temporary state of resource exhaustion that occurs after an individual excessively utilizes their limited self-control resources. As a result, performance on subsequent cognitive tasks, including prospective memory (PM), may be impaired. The present study examined how ego depletion influences time-based prospective memory (TBPM) across two experiments. In Experiment 1, 164 participants (aged 18-25, M = 21.09, SD = 1.24) were assigned to a low-difficulty control group (N = 44), a high-difficulty control group (N = 41), a low-difficulty depletion group (N = 37), or a high-difficulty depletion group (N = 42). Results showed that ego depletion impaired TBPM performance, and this effect was not moderated by task difficulty. The impairment appeared to result primarily from reduced effectiveness of both internal and external attention. Experiment 2 investigated whether reminders could ameliorate TBPM deficits following depletion. Seventy-six participants (aged 18-25, M = 22.50, SD = 1.09) were assigned to a control group (N = 24), a recent reminder group (N = 26), or a distant reminder group (N = 26). Results indicated that recent reminders significantly improved TBPM performance, suggesting that explicit cues can markedly enhance prospective memory under ego-depletion conditions. This finding provides a low-cost and highly efficient cognitive strategy for contexts characterized by high cognitive load and low motivation (e.g., intensive work, learning, or clinical rehabilitation training). By optimizing the design of external cues, such strategies can help individuals maintain effective goal-directed task performance even when self-control resources are limited.