Kennedy A, Brysbaert M, Murray W S
Psychology Department, University, Dundee, Scotland, U.K.
Q J Exp Psychol A. 1998 Feb;51(1):135-51. doi: 10.1080/713755746.
Two experiments are described in which eye movements were monitored as subjects performed a simple target-spotting task under conditions of intermittent illumination produced by varying the display-screen frame rate on a computer VDU. In Experiment 1, subjects executed a saccade from a fixation point to a target which appeared randomly at a fixed eccentricity of 14 character positions to the left or right. Saccade latency did not differ reliably as a function of screen refresh rate, but average saccade extent at 70 Hz and 110 Hz was reliably shorter than at 90 Hz and 100 Hz. Experiment 2 examined the same task using a range of target eccentricities (7, 14, and 28 character positions to the left and right) and across a wider range of screen refresh rates. The results confirmed the curvilinear relationship obtained in Experiment 1, with average saccade extent reliably shorter at refresh rates of 50 Hz and 125 Hz than at 75 Hz and 100 Hz. While the effect was greater for remote targets, analyses of the proportional target error failed to show a reliable interaction between target eccentricity and display refresh rate. In contrast to Experiment 1, there was a pronounced effect of refresh rate on saccade latency (corrected for time to write the screen frame), with shorter latencies at higher refresh rates. It may be concluded that pulsation at frequencies above fusion disrupts saccade control. However, the curvilinear functional relationship between screen refresh rate and saccade extent obtained in these studies differs from previously reported effects of intermittent illumination on the average size of "entry saccades" (the first saccade to enter a given word) in a task involving word identification (Kennedy & Murray, 1993a, 1996). This conflict of data may arise in part because within-word adjustments in viewing position, which are typical of normal reading, influence measures of average saccade extent.
本文描述了两项实验，实验中在计算机视频显示器上通过改变显示屏帧率产生间歇性照明条件，让受试者执行简单的目标定位任务时对其眼动进行监测。在实验1中，受试者从一个固定点进行扫视，看向在左侧或右侧14个字符位置的固定偏心率处随机出现的目标。扫视潜伏期并未随屏幕刷新率的变化而产生可靠差异，但在70赫兹和110赫兹时的平均扫视幅度确实比在90赫兹和100赫兹时可靠地更短。实验2使用了一系列目标偏心率（左右7、14和28个字符位置）并在更广泛的屏幕刷新率范围内研究了相同任务。结果证实了在实验1中获得的曲线关系，在50赫兹和125赫兹刷新率下的平均扫视幅度比在75赫兹和100赫兹时可靠地更短。虽然对较远目标的影响更大，但对目标比例误差的分析未能显示目标偏心率与显示刷新率之间存在可靠的交互作用。与实验1不同的是，刷新率对扫视潜伏期（校正屏幕帧写入时间后）有显著影响，刷新率越高潜伏期越短。可以得出结论，高于融合频率的脉动会干扰扫视控制。然而，这些研究中获得的屏幕刷新率与扫视幅度之间的曲线函数关系不同于先前报道的在涉及单词识别的任务中（肯尼迪和默里，1993a，1996）间歇性照明对“进入扫视”（进入给定单词的第一个扫视）平均大小的影响。数据冲突可能部分源于正常阅读中典型的词内注视位置调整会影响平均扫视幅度的测量。
