Stimulus competition mediates the joint effects of spatial and feature-based attention.
Stimulus competition mediates the joint effects of spatial and feature-based attention.
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DOI：
10.1167/15.14.7
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发表时间：
2015
影响因子：
1.8
通讯作者：
Alex L. White;M. Rolfs;M. Carrasco
中科院分区：
文献类型：
--
作者：
Alex L. White;M. Rolfs;M. Carrasco
不同的注意机制增强了视觉刺激的感觉处理，这些视觉刺激出现在任务相关的位置，并具有任务相关的特征。我们使用心理物理学和计算模型相结合的方法来研究这两种类型的注意力--空间注意力和基于特征的注意力--在一项任务中如何相互作用来调节敏感度。观察者监测重叠的一组点的颜色饱和度的目标变化，他们必须将其定位为位于上半视野或下半视野。预先提示指示目标最可能的位置(左/右)、颜色(红/绿)或位置和颜色。我们测量了位置线索和颜色线索的每一种组合的灵敏度(d‘)，每一种组合都可能是有效的、中性的或无效的。当三个相互竞争的饱和度变化与目标变化同时发生时，存在明显的交互作用：被线索颜色的空间线索效应最强，且被线索位置的颜色线索效应最强。在第二个实验中，只有目标点组改变了饱和度，因此刺激竞争较低。由此产生的线索效应在统计上是独立的和相加的：颜色线索效应在有人值守和无人值守的位置上同样强烈。我们用一个计算模型来解释这些数据，在这个模型中，空间和基于特征的注意力独立地调节感觉反应的增益，与皮质活动的测量一致。然后，多种回应通过分裂的正常化进行竞争。尽管注意系统本身是独立的，但充分的竞争会在两种提示效应之间产生交互作用。这个模型有助于调和看似不同的行为和生理发现。
Distinct attentional mechanisms enhance the sensory processing of visual stimuli that appear at task-relevant locations and have task-relevant features. We used a combination of psychophysics and computational modeling to investigate how these two types of attention--spatial and feature based--interact to modulate sensitivity when combined in one task. Observers monitored overlapping groups of dots for a target change in color saturation, which they had to localize as being in the upper or lower visual hemifield. Pre-cues indicated the target's most likely location (left/right), color (red/green), or both location and color. We measured sensitivity (d') for every combination of the location cue and the color cue, each of which could be valid, neutral, or invalid. When three competing saturation changes occurred simultaneously with the target change, there was a clear interaction: The spatial cueing effect was strongest for the cued color, and the color cueing effect was strongest at the cued location. In a second experiment, only the target dot group changed saturation, such that stimulus competition was low. The resulting cueing effects were statistically independent and additive: The color cueing effect was equally strong at attended and unattended locations. We account for these data with a computational model in which spatial and feature-based attention independently modulate the gain of sensory responses, consistent with measurements of cortical activity. Multiple responses then compete via divisive normalization. Sufficient competition creates interactions between the two cueing effects, although the attentional systems are themselves independent. This model helps reconcile seemingly disparate behavioral and physiological findings.