Various researchers have proposed pupillometric indicators to assess a person's cognitive strain. However, to distinguish the variation of pupil light response from psychosensory pupil response in experimental field conditions is a challenge. The Index of Cognitive Activity (ICA) addresses this problem by wavelet separation. This research investigates the ICA's sensitivity for multiple level task-evoked cognitive activity and visual influences concerning informational work tasks. Objective and subjective measures assessed cognitive strain of participants (N = 22) during various tasks. In a first experiment, mental arithmetic tasks were used to induce different levels of cognitive activity. In a second experiment, influences of screen polarity and presentation of information were investigated (N = 18). The results indicate that eye metrics are rarely sensitive to slight variations in task difficulty. Moreover, the ICA is likely to be sensitive towards constant screen illumination and shows tendencies regarding changes in displayed information. Possible ramifications for the objective assessment of cognitive strain are discussed.

各种研究人员提出了瞳孔测量指标来评估一个人的认知压力。然而，在实验现场条件下区分瞳孔光反应和心理感觉瞳孔反应的变化是一个挑战。认知活动指数 (ICA) 通过小波分离解决了这个问题。本研究调查了 ICA 对多层次任务诱发的认知活动的敏感性以及有关信息工作任务的视觉影响。客观和主观措施评估了参与者 ( N  = 22) 在各种任务中的认知压力。在第一个实验中，使用心算任务来诱导不同水平的认知活动。在第二个实验中，研究了屏幕极性和信息呈现的影响（N = 18）。结果表明，眼睛指标很少对任务难度的细微变化敏感。此外，ICA 可能对恒定的屏幕照明很敏感，并显示出有关显示信息变化的趋势。讨论了客观评估认知压力的可能后果。