Searching for unknown feature targets on more than one dimension: Investigating a ''dimension-weighting'' account
Searching for unknown feature targets on more than one dimension: Investigating a ''dimension-weighting'' account
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DOI：
10.3758/bf03205479
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发表时间：
1996-01-01
期刊：
影响因子：
--
通讯作者：
Muller, HJ
中科院分区：
文献类型：
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作者：
Found, A;Muller, HJ
当目标可以存在于多个维度中的一个而不是仅存在于一个维度时，搜索单个特征目标所需的时间更长(Muller，Heller，&Ziegler，1995；Treisman，1988)。穆勒等人将这一成本归因于识别目标维度的需要。他们提出了一种维度加权帐户，在该帐户中，主地图单元并行计算特定维度显著信号的加权和。如果预先知道目标维度，则来自该维度的信号被放大。但是，如果目标维度未知，则在将权重从非目标维度转移到目标维度的过程中确定目标维度。这样产生的权重模式在多个试验之间持续存在，为与先前目标(试验n)在维度上相同的目标(试验n+1)产生试验间便利。在本研究中，我们采用了一套新的任务来重新审查和扩展这一账户。目标沿着两个可能的维度(颜色或方向)定义，并且可以具有两个特征值之一(例如，红色或蓝色)。实验1和实验2分别要求对单个目标进行缺席/在场和颜色/方位辨别。他们发现：(1)这两项任务都涉及重量转移，尽管(明确地)辨别目标的维度除了简单地检测其存在之外，还需要一些额外的过程；(2)试验间促进确实(主要)是维度特定的，而不是本质上的特征特定的。在实验3中，任务是计算显示器中的目标数量(三个或四个)，这些目标可以是维度上相同的(所有颜色或所有方向)，也可以是混合的(一些颜色和一些方向)。正如维度加权账户所预测的那样，列举在同一维度中定义的四个目标比计算两个维度中定义的三个这样的目标或混合目标要快。
Search for odd-one-out feature targets takes longer when the target can be present in one of several dimensions as opposed to only one dimension (Muller, Heller, & Ziegler, 1995; Treisman, 1988). Muller et al, attributed this cost to the need to discern the target dimension. They proposed a dimension-weighting account, in which master map units compute, in parallel, the weighted sum of dimension-specific saliency signals. if the target dimension is known in advance, signals from that dimension are amplified. But if the target dimension is unknown, it is determined in a process that shifts weight from the nontarget to the target dimension. The weight pattern thus generated persists across trials, producing intertrial facilitation for a target (trial n+1) dimensionally identical to the preceding target (trial n). In the present study, we employed a set of new tasks in order to reexamine and extend this account. Targets were defined along two possible dimensions (color or orientation) and could take on one of two feature values (e.g., red or blue). Experiments 1 and 2 required absent/present and color/orientation discrimination of a single target, respectively. They showed that (1) both tasks involve weight shifting, though (explicitly) discerning the dimension of a target requires some process additional to simply detecting its presence; and (2) the intertrial facilitation is indeed (largely) dimension specific rather than feature specific in nature. In Experiment 3, the task was to count the number of targets in a display (either three or four), which could be either dimensionally the same (all color or all orientation) or mixed (some color and some orientation). As predicted by the dimension-weighting account, enumerating four targets all defined within the same dimension was faster than counting three such targets or mixed targets defined in two dimensions.