Lo Shih-Yu, Howard Christina J, Holcombe Alex O
School of Psychology, University of Sydney, Australia.
Vision Res. 2012 Jun 15;63:20-33. doi: 10.1016/j.visres.2012.04.021. Epub 2012 May 9.
According to a limited-resource account of feature-based attention, dividing feature-based attention by selecting targets on the basis of different features dilutes its power. Multiple-feature costs have been documented previously, but it is not clear whether the multiple-feature cost arose at the selection (segregating targets from non-targets) stage predicted by the limited-resource account. The cost might instead result from a post-selection difficulty in processing or accessing the contents of the targets. By defining the targets with a selection attribute (color) that is very distinct from the attribute participants must access and report (spatial period), we were able to manipulate the selection process independently from the access stage. We still found a cost for different selection features (colors), suggesting that multiple-feature costs can arise at the selection stage. The cost was only significant however when distracters were present that shared the selection features. The cost manifested not only as greater errors or less precision in reporting the access attribute (spatial period), but also as an increased temporal lag between the physical stimuli and the reported percept. In summary, splitting selection among different features incurred little or no penalty by itself, but selection interference by distracters sharing target features could be large and could slow processing.
根据基于特征的注意的有限资源理论，基于不同特征选择目标来分配基于特征的注意会削弱其效力。先前已记录了多特征代价，但尚不清楚多特征代价是否出现在有限资源理论所预测的选择（将目标与非目标分离）阶段。相反，这种代价可能源于选择后处理或获取目标内容时的困难。通过用一种与参与者必须获取和报告的属性（空间周期）截然不同的选择属性（颜色）来定义目标，我们能够独立于获取阶段来操纵选择过程。我们仍然发现了不同选择特征（颜色）的代价，这表明多特征代价可能出现在选择阶段。然而，只有当存在共享选择特征的干扰项时，这种代价才显著。这种代价不仅表现为报告获取属性（空间周期）时更大误差或更低精度，还表现为物理刺激与报告的感知之间时间延迟增加。总之，在不同特征之间进行选择本身几乎不会产生代价，但共享目标特征的干扰项造成的选择干扰可能很大，并且会减慢处理速度。
