Lavine Robert A, Sibert John L, Gokturk Mehmet, Dickens Ben
School of Medicine and Health Sciences and School of Engineering and Applied Sciences, The George Washington University, Washington, DC, USA.
Aviat Space Environ Med. 2002 Apr;73(4):367-72.
Visual scanning is necessary for aviation safety and similar vigilance tasks, but little is known about its characteristics in such tasks, including possible changes with alertness and fatigue. We explored concurrent eye movements and human performance during a vigilance task designed to require frequent visual scanning. Effects of time and auditory stimuli were examined.
A corneal-reflectance, PC-based system (Eyegaze Development System, LC Technologies) provided eye movement measures. Stimuli were four digits in a rectangular array, changed at an event rate of 4 s for a task duration of 30 min. There were 20 subjects who were asked to respond to specific, infrequent signal arrays by bar press, under both 50 dBA white noise and 90 dBA intermittent and unpredictable sound-burst conditions, counterbalanced for order.
With time-on-task, subjective fatigue ratings increased, dwell time defined as the total duration of fixations on target digits decreased, number of fixations decreased, and fixations were further from target digits in both conditions. Fixation durations [mean (M) = 258 ms; standard deviation (SD) = 54 ms] did not change significantly with time or condition. Off-target visual scan-paths were less frequently followed by hits than were on-target scan-paths in both conditions. With the sound-burst condition, fixations were closer to target digits and hit rates increased.
Dwell time, number, and accuracy of fixations on target objects decreased with time on task, and inaccurate scan-paths were often associated with performance errors. Sound bursts increased fixation accuracy and hit rate. The results provide a basis for visual scan analyses during vigilance tasks, with applications to alertness monitoring and prediction.
视觉扫描对于航空安全及类似的警戒任务至关重要，但对于此类任务中视觉扫描的特征，包括其随警觉性和疲劳可能发生的变化，我们知之甚少。我们在一项旨在要求频繁视觉扫描的警戒任务中探究了同时发生的眼动和人类表现。研究了时间和听觉刺激的影响。
基于个人计算机的角膜反射系统（眼动注视开发系统，LC技术公司）提供眼动测量数据。刺激物是呈矩形阵列排列的四个数字，以4秒的事件发生率变化，任务持续时间为30分钟。有20名受试者被要求在50分贝A白噪声和90分贝A间歇性且不可预测的突发声音条件下，通过按压杠杆对特定的、不频繁出现的信号阵列做出反应，两种条件的顺序进行了平衡。
随着任务持续时间的增加，主观疲劳评分升高，定义为对目标数字注视的总持续时间的停留时间减少，注视次数减少，并且在两种条件下注视点离目标数字更远。注视持续时间[平均值（M）=258毫秒；标准差（SD）=54毫秒]在时间或条件方面没有显著变化。在两种条件下，与目标扫描路径相比，偏离目标的视觉扫描路径被命中的频率更低。在突发声音条件下，注视点更靠近目标数字且命中率增加。
随着任务时间的增加，对目标物体的注视停留时间、次数和准确性降低，不准确的扫描路径通常与表现错误相关。突发声音提高了注视准确性和命中率。这些结果为警戒任务期间的视觉扫描分析提供了基础，可应用于警觉性监测和预测。
