Literature has occasionally reported acute effects of office illuminance on cognitive performance during daytime. The current study was conducted to systematically investigate whether the type of task and level of task difficulty moderate the effect of daytime illuminance on cognitive functioning. Thirty healthy participants were assigned to high (∼1036 lux at eye level; melanopic EDI = 904 lux) vs. low (∼108 lux at eye level, melanopic EDI = 87 lux) illuminance (at 6500 K) during working hours, in which participants were tested on both easy and difficult versions of tasks probing sustained attention, response inhibition, conflict monitoring and working memory. Subjective sleepiness and mood were also measured. Results revealed that exposure to high vs. low illuminance significantly improved speed on the response inhibition task, and accuracy and speed on the working memory tasks. Moreover, when effects arose, these were moderated by task difficulty, consistently showing more pronounced effects for easy than for difficult trials. Notably, subjective sleepiness and negative mood remained unaffected by illuminance, and no statistically significant effects emerged for sustained attention and conflict monitoring. This study demonstrates that the diurnal cognitive effects of illuminance may be moderated by both types of cognitive task and task difficulty.

文献偶尔报道了办公室照度对白天认知表现的急性影响。进行本研究的目的是系统地研究任务的类型和任务难度的水平是否减轻了白天照度对认知功能的影响。30名健康参与者在工作时间内被分配为高（在6500 K下）照度（在眼水平时约为1036 lux；黑素EDI = 904 lux）与低（在眼水平时约为108 lux，黑素EDI = 87 lux）。参与者在容易和困难的任务上均经过测试，以探测持续的注意力，反应抑制，冲突监控和工作记忆。还测量了主观嗜睡和情绪。结果表明，暴露于高照度与低照度下可显着提高响应抑制任务的速度，工作记忆任务的准确性和速度。而且，当出现效果时，这些效果会因任务难度而缓和，始终如一地显示出比困难试验更明显的效果。值得注意的是，主观嗜睡和消极情绪仍然不受照度的影响，持续关注和冲突监测没有统计学上的显着影响。这项研究表明，照度的昼夜认知效应可以通过认知任务的类型和任务难度来缓解。对于持续关注和冲突监控，没有统计学上的显着影响。这项研究表明，照度的昼夜认知效应可以通过认知任务的类型和任务难度来缓解。对于持续关注和冲突监控，没有统计学上的显着影响。这项研究表明，照度的昼夜认知效应可以通过认知任务的类型和任务难度来缓解。