The present study examined the involvement of subcortical structures in the processing of global and local information. To this end, we used a stereoscope to present hierarchical stimuli (global shapes composed of local elements) in a dichoptic or a monocular fashion, such that global and local information was either presented to the same eye (same-eye condition) or segregated between the eyes (different-eyes condition). In Experiment 1, the typical global advantage and global-to-local interference were observed for the same-eye presentation condition. On the other hand, no indication of a global advantage or of global-to-local interference emerged in the different-eyes presentation condition. In Experiment 2 we replicated these results, ruling out a possible alternative explanation that the pattern of results observed for the different-eyes presentation condition resulted merely from segregation of the stimulus between the eyes. Rather, the experiment demonstrated that the global-to-local interference was eliminated only when global and local information was segregated between the eyes. Taken together, these findings suggest that processing the global aspect of hierarchical stimuli involves subcortical regions indexed by monocular portions of the visual system.

本研究检查了皮层下结构在处理全球和本地信息中的参与。为此，我们使用了一个立体镜以分叉或单眼的方式呈现了分层的刺激（由局部元素组成的整体形状），这样全局和局部信息要么呈现给同一只眼（同一眼条件），要么被隔离在眼睛（不同眼睛的状况）。在实验1中，对于同一只眼睛呈现条件，观察到典型的全局优势和全局-局部干扰。另一方面，在不同的眼睛呈现条件下，没有出现全球优势或全球对本地干扰的迹象。在实验2中，我们复制了这些结果，排除一个可能的替代解释，即针对不同眼睛呈现条件所观察到的结果模式仅是由于眼睛之间的刺激隔离所致。相反，该实验表明，只有在眼睛之间隔离了全局和局部信息时，才能消除全局对局部的干扰。综上所述，这些发现表明，处理分级刺激的全局方面涉及由视觉系统的单眼部分索引的皮层下区域。