Siebold Alisha, Donk Mieke
Department of Cognitive Psychology, Free University, Amsterdam, the Netherlands.
PLoS One. 2014 Jun 13;9(6):e99707. doi: 10.1371/journal.pone.0099707. eCollection 2014.
The goal of the current study was to investigate time-dependent effects of the number of targets presented and its interaction with stimulus salience on oculomotor selection performance. To this end, observers were asked to make a speeded eye movement to a target orientation singleton embedded in a homogeneous background of vertically oriented lines. In Experiment 1, either one or two physically identical targets were presented, whereas in Experiment 2 an additional orientation-based salience manipulation was performed. The results showed that the probability of a singleton being available for selection is reduced in the presence of an identical singleton (Experiment 1) and that this effect is modulated by the salience of the other singleton (Experiment 2). While the absolute orientation contrast of a target relative to the background contributed to the probability that it is available for selection, the crucial factor affecting selection was the relative salience between singletons. These findings are incompatible with a processing speed account, which highlights the importance of visibility and claims that a certain singleton identity has a unique speed with which it can be processed. In contrast, the finding that the number of targets presented affected a target's availability suggests an important role of the broader display context in determining oculomotor selection performance.
本研究的目的是调查呈现的目标数量的时间依赖性效应及其与刺激显著性的相互作用对眼动选择性能的影响。为此，要求观察者快速将眼球移向嵌入垂直定向线条的均匀背景中的目标方向单独元素。在实验1中，呈现一个或两个物理上相同的目标，而在实验2中，进行了额外的基于方向的显著性操纵。结果表明，在存在相同单独元素的情况下，单独元素可供选择的概率会降低（实验1），并且这种效应会受到另一个单独元素的显著性的调节（实验2）。虽然目标相对于背景的绝对方向对比度有助于其可供选择的概率，但影响选择的关键因素是单独元素之间的相对显著性。这些发现与一种处理速度观点不一致，该观点强调可见性的重要性，并声称某个单独元素身份具有其可被处理的独特速度。相比之下，呈现的目标数量影响目标可供性的发现表明，更广泛的显示背景在确定眼动选择性能方面起着重要作用。
