Carrasco M, Ponte D, Rechea C, Sampedro M J
Department of Psychology, New York University, NY 10003-6634, USA.
Percept Psychophys. 1998 Oct;60(7):1243-58. doi: 10.3758/bf03206173.
It has been stated that whereas between-dimension (color x orientation) conjunctions can be searched in a "parallel" fashion, within-dimension (color x color) conjunctions are necessarily searched in a "serial self-terminating" fashion (Wolfe et al., 1990). We explored the effects of practice (within 1-h experimental session) and distractor grouping on within-dimension conjunction search tasks. In Experiments 1 and 3, the stimuli were rectangles formed by two adjacent squares; in Experiment 2, the stimuli were plus signs formed by two segments and an intersection. In Experiments 1 and 2, observers were assigned to one of two experimental conditions: In one, all the distractors shared a simple feature (the color blue); in the other, distractors did not share that simple feature. In the first condition, search became more efficient with practice and observers' performance was characterized by a shallow reaction time (RT) x set size slope; in the second condition, observers' performance did not improve as much with practice. We propose that the differential effects of practice between these two experimental conditions can be explained in terms of distractor grouping induced by the shared color of the distractors. Experiment 3 showed that, with practice, a shallow RT x set size slope characterized observers' search for a color x color target among four different distractors that shared a common color. The present results contradict a main tenet of some current visual search models--namely, that within-dimension conjunctions cannot be searched in parallel, and question the validity of using RT x set size slope functions to distinguish between preattentive versus attentive search.
有人指出，虽然维度间（颜色×方向）的联合搜索可以以“平行”方式进行，但维度内（颜色×颜色）的联合搜索必然是以“系列自终止”方式进行（沃尔夫等人，1990）。我们探讨了练习（在1小时的实验过程中）和干扰项分组对维度内联合搜索任务的影响。在实验1和3中，刺激物是由两个相邻正方形组成的矩形；在实验2中，刺激物是由两条线段和一个交点组成的加号。在实验1和2中，观察者被分配到两种实验条件之一：一种条件下，所有干扰项都具有一个简单特征（蓝色）；另一种条件下，干扰项不具有该简单特征。在第一种条件下，随着练习搜索变得更有效率，观察者的表现以较浅的反应时间（RT）×集合大小斜率为特征；在第二种条件下，观察者的表现随练习提升幅度较小。我们认为，这两种实验条件下练习的不同效果可以用干扰项共享颜色所引发的干扰项分组来解释。实验3表明，通过练习，观察者在四个共享一种共同颜色的不同干扰项中搜索颜色×颜色目标时，其搜索表现以较浅的RT×集合大小斜率为特征。目前的结果与一些当前视觉搜索模型的一个主要原则相矛盾——即维度内联合搜索不能平行进行，并且质疑使用RT×集合大小斜率函数来区分前注意搜索与注意搜索的有效性。
