Hooge I T, Erkelens C J
Helmholtz Institute, Utrecht University, The Netherlands.
Percept Psychophys. 1996 Oct;58(7):969-76. doi: 10.3758/bf03206825.
To obtain insight into the control of fixation duration during visual search, we had 4 subjects perform simple search tasks in which we systematically varied the discriminability of the target. The experiment was carried out under two conditions. Under the first condition (blocked), the discriminability of the target was kept constant during a session. Under the second condition (mixed), the discriminability of the target varied per trial. Under the blocked condition, fixation duration increased with decreasing discriminability. For 2 subjects, we found much shorter fixation durations in difficult trials with the mixed condition than in difficult trials with the blocked condition. Overall, the subjects fixated the target, continued to search, and then went back to the target in 5%-55% of the correct trials. In these trials, the result of the analysis of the foveal target was not used for preparing the next saccade. The results support a preprogramming model of the control of fixation duration. In a simple search task, control of fixation duration appears to be indirect.
为深入了解视觉搜索过程中注视持续时间的控制，我们让4名受试者执行简单的搜索任务，在此过程中我们系统地改变目标的可辨别性。实验在两种条件下进行。在第一种条件（分组）下，目标的可辨别性在一个阶段内保持恒定。在第二种条件（混合）下，目标的可辨别性在每次试验中都有所变化。在分组条件下，注视持续时间随着可辨别性的降低而增加。对于2名受试者，我们发现在混合条件下的困难试验中，注视持续时间比在分组条件下的困难试验中短得多。总体而言，在5%-55%的正确试验中，受试者注视目标、继续搜索，然后再回到目标。在这些试验中，中央凹目标的分析结果未用于准备下一次扫视。这些结果支持了注视持续时间控制的预编程模型。在简单搜索任务中，注视持续时间的控制似乎是间接的。
