Wong Elaine M Y, Roeber Urte, Freeman Alan W
School of Medical Sciences, University of Sydney, Australia.
J Vis. 2010 Jan 29;10(1):14.1-12. doi: 10.1167/10.1.14.
The stimulus at any point in the visual field is rarely static during normal viewing: observer and object movement conspire to produce a continually changing series of stimuli. Our aim was to study both the short- and long-term interactions between responses to a series of stimuli presented at a single visual location. We used rapid serial visual presentation (RSVP) in which the stimuli were randomly oriented gratings delivered at the rate of 30 per second. Human subjects pressed a key whenever they saw a target orientation, for example horizontal. The results were analyzed by finding two orientations before each key-press. The first preceded the key-press by the reaction time, and the second preceded the first by an interval of variable duration. There were two main findings. First, the subject was more likely to press the key when the target was immediately preceded by a grating of similar orientation. This facilitation presumably results from the summation of sub-threshold inputs. Second, a key-press was reduced in probability when a target orientation was preceded by a similar orientation with an interstimulus interval of 100-400 ms. The time course of this suppression is similar to that seen in attentional blink experiments.
在正常观看过程中，视野中任何一点的刺激很少是静止不变的：观察者和物体的移动共同作用，产生一系列不断变化的刺激。我们的目的是研究对在单个视觉位置呈现的一系列刺激的反应之间的短期和长期相互作用。我们使用了快速序列视觉呈现（RSVP），其中刺激是每秒30次呈现的随机取向光栅。每当人类受试者看到目标取向（例如水平取向）时，就按下一个按键。通过在每次按键之前找到两个取向来分析结果。第一个取向在按键之前出现的时间为反应时间，第二个取向在第一个取向之前出现，间隔时间可变。有两个主要发现。第一，当目标之前紧接着是取向相似的光栅时，受试者更有可能按下按键。这种促进作用大概是由阈下输入的总和导致的。第二，当目标取向之前是取向相似的光栅，且刺激间隔为100 - 400毫秒时，按键的概率会降低。这种抑制的时间进程与注意瞬脱实验中观察到的相似。
