Fehringer Benedict C O F
University of Mannheim, Germany.
J Eye Mov Res. 2021 Jun 11;14(2). doi: 10.16910/jemr.14.2.4. eCollection 2021.
The Index of Cognitive Activity (ICA) and its open-source alternative, the Index of Pupillary Activity (IPA), are pupillary-based indicators for cognitive workload and are independent of light changes. Both indicators were investigated regarding influences of cognitive demand, fatigue and inter-individual differences. In addition, the variability of pupil changes between both eyes (difference values) were compared with the usually calculated pupillary changes averaged over both eyes (mean values). Fifty-five participants performed a spatial thinking test, the R-Cube-Vis Test, with six distinct difficulty levels and a simple fixation task before and after the R-Cube-Vis Test. The distributions of the ICA and IPA were comparable. The ICA/IPA values were lower during the simple fixation tasks than during the cognitively demanding R-Cube-Vis Test. A fatigue effect was found only for the mean ICA values. The effects of both indicators were larger between difficulty levels of the test when inter-individual differences were controlled using z-standardization. The difference values seemed to control for fatigue and appeared to differentiate better between more demanding cognitive tasks than the mean values. The derived recommendations for the ICA/IPA values are beneficial to gain more insights in individual performance and behavior during, e.g., training and testing scenarios.
认知活动指数（ICA）及其开源替代指标瞳孔活动指数（IPA）是基于瞳孔的认知负荷指标，且不受光线变化影响。对这两个指标在认知需求、疲劳和个体差异方面的影响进行了研究。此外，还比较了双眼瞳孔变化的差异值与通常计算的双眼平均瞳孔变化值（平均值）。55名参与者进行了一项空间思维测试，即R-立方体视觉测试，该测试有六个不同难度级别，且在R-立方体视觉测试前后进行了简单的注视任务。ICA和IPA的分布具有可比性。在简单注视任务期间，ICA/IPA值低于认知要求较高的R-立方体视觉测试期间。仅在ICA平均值上发现了疲劳效应。当使用z标准化控制个体差异时，两个指标在测试难度级别之间的效应更大。差异值似乎可以控制疲劳，并且在区分要求更高的认知任务方面似乎比平均值表现更好。得出的ICA/IPA值建议有助于在例如训练和测试场景中更深入了解个体表现和行为。
