自发性眨眼对瞳孔反应和注视位置的影响

The Influence of Spontaneous Blinks on the Pupil Response and Fixation Position

瞳孔反应和注视位置是眼动研究中重要的监测指标,但在实验过程中,常常会受到自发性眨眼的干扰.目前,多数研究者只关注到眨眼过程中短暂的数据丢失和波动,而忽略了眨眼对这些变量更广泛的影响.因此本文系统地分析了眨眼对瞳孔反应和注视位置的影响.本研究采用简单的长时间注视任务,使用光学眼动仪记录22个人类被试的瞳孔和注视位置的数据并在其中精确地提取眨眼.瞳孔反应和注视位置的时间序列以眨眼开始和结束对齐.结果表明,在眨眼结束后,瞳孔反应发生长达4 s的大幅度波动（约12％）,其中在300～1 700 ms间,瞳孔值显著地低于基线水平（P＜ FDR0.05）.同时,眨眼会造成持续约200 ms、最大幅度约1 a的显著的注视位置偏移（P＜FDR0.05）.此外,由眨眼引起的瞳孔变化也会造成同步的注视位置偏移的伪迹,最大偏移幅度为0.26＆#176;.因此,眨眼对瞳孔反应和注视位置的影响远超出眨眼过程本身,在基于眼动的实验研究中,这一影响应得到更多的重视,并且在实验结果的解释中应充分考虑到眨眼的影响.

The pupil response and fixation position are important variables in eye movement researches. However, they are susceptive to the disturbance of eye blinks. While most studies only focus on the data missing and fluctuation during blinks, but neglect the more extensive influence of blinks on pupil response and fixation position. Thus, present study aims to precisely examine the impacts of blink on pupil response and fixation position. We recorded the pupil size and fixation position using a video eye tracker, and indentifying the blinks based on these data in a simple prolonged fixation task. The temporal sequence was relined to the onset and end of the detected blinks. We observed a large fluctuation （ approximately 12% ） in the pupil response, which last approximately 4 seconds after the ending of eye blink. During this period, the pupil size was significantly smaller than the baseline from 300 to 1700 ms （P 〈 FDR005）. Meanwhile, the fixation errors induced by blinks amount to approximately 1° within the initial 200 ms after the ending of blinks, which was significantly greater than the baseline （P 〈 FDR0.05 ）. Moreover, the blink-induced pupil variation could artificially bias the recorded eye position（with a maximum of 0.26°in the present study）. Our results suggest that the spontaneous blinks affect the pupil size and fixation position to a much larger extent and longer duration than commonly assumed, which should be taken into consideration in the careful explanation of eye movement related experimental results.