Ayasse Nicolai D, Wingfield Arthur
Volen National Center for Complex Systems, Brandeis University, Waltham, MA, United States.
Front Psychol. 2020 Jan 10;10:2947. doi: 10.3389/fpsyg.2019.02947. eCollection 2019.
Task-evoked changes in pupil dilation have long been used as a physiological index of cognitive effort. Unlike this response, that is measured during or after an experimental trial, the baseline pupil dilation (BPD) is a measure taken prior to an experimental trial. As such, it is considered to reflect an individual's arousal level in anticipation of an experimental trial. We report data for 68 participants, ages 18 to 89, whose hearing acuity ranged from normal hearing to a moderate hearing loss, tested over a series 160 trials on an auditory sentence comprehension task. Results showed that BPDs progressively declined over the course of the experimental trials, with participants with poorer pure tone detection thresholds showing a steeper rate of decline than those with better thresholds. Data showed this slope difference to be due to participants with poorer hearing having larger BPDs than those with better hearing at the start of the experiment, but with their BPDs approaching that of the better hearing participants by the end of the 160 trials. A finding of increasing response accuracy over trials was seen as inconsistent with a fatigue or reduced task engagement account of the diminishing BPDs. Rather, the present results imply BPD as reflecting a heightened arousal level in poorer-hearing participants in anticipation of a task that demands accurate speech perception, a concern that dissipates over trials with task success. These data taken with others suggest that the baseline pupillary response may not reflect a single construct.
长期以来，任务诱发的瞳孔扩张变化一直被用作认知努力的生理指标。与在实验试验期间或之后测量的这种反应不同，基线瞳孔扩张（BPD）是在实验试验之前进行的测量。因此，它被认为反映了个体在预期实验试验时的唤醒水平。我们报告了68名年龄在18至89岁之间参与者的数据，他们的听力从正常听力到中度听力损失不等，在一项听觉句子理解任务的160次试验系列中进行了测试。结果表明，在实验试验过程中，BPD逐渐下降，纯音检测阈值较差的参与者的下降速度比阈值较好的参与者更陡。数据表明，这种斜率差异是由于听力较差的参与者在实验开始时的BPD比听力较好的参与者更大，但在160次试验结束时，他们的BPD接近听力较好的参与者。在试验中发现反应准确性提高，这与BPD下降的疲劳或任务参与度降低的解释不一致。相反，目前的结果意味着BPD反映了听力较差的参与者在预期需要准确语音感知的任务时的唤醒水平提高，这种担忧随着试验成功而消散。这些数据与其他数据一起表明，基线瞳孔反应可能并不反映单一的结构。
