连续闪现抑制下对洞的无意识知觉

Implicit Perception of "Holes" Under Continuous Flash Suppression

大量收敛一致的实验证据表明,图形的大范围性质可以由拓扑性质来描述,并且其检测发生在视觉过程的最早期,这些证据几乎全部来自对意识上知觉的研究,而拓扑性质的意识下加工机制尚有待发掘.意识下知觉是人的感官系统客观上接受刺激呈现但主观上没有察觉的知觉,其机制和应用长期以来一直是知觉研究的热点.本文采用了一种双眼竞争的变式——连续闪现抑制,将待检测的刺激图形掩蔽,使之处于意识下状态,考察意识下知觉中拓扑性质的加工."洞的个数"作为一种拓扑性质是本文的研究对象.通过量度被抑制图形从发生变化到被知觉的被抑制时间,或者被试对被抑制的变化图形的正确检测率,我们发现,相比于不变或者各种非拓扑性质变化,意识下知觉中的拓扑性质(洞的个数)的变化会使图形更快、更容易被检测到.本研究揭示了拓扑性质(洞的个数)在意识下知觉中的优先性,将拓扑知觉理论从意识上知觉领域拓展到了意识下知觉领域,为拓扑性质加工的早期性提供了有力的证据;另一方面,本研究也提示了拓扑性质经由皮层下视通路加工处理的可能性.

The Global First theory considers the global properties of objects could be described as topological invariants, with the earliest detection and highest priority in visual processing. The theory is supported by accumulating evidence in conscious vision, but remains unclear in implicit perception, the perception in the absence of awareness, whose mechanism and application have been studied a lot in cognition research for years. In the present study we probed into the processing of global properties in implicit perception by means of a variant of binocular rivalry called continuous flash suppression, in which our target stimuli were suppressed by dynamic mosaic noise patterns in order to achieve subconscious vision. The number of holes, a crucial topological invariant of an object, is the target of this study. In Exp1, the disk, the S and the O shape were used as target stimuli, the shapes might change or not after being suppressed, subjects reported the breakthrough of suppressed figures by keypress, we measured the suppression time of the figures, and found stimuli of topological changes（changes of numbers of holes in stimuli） took significantly less time to get into dominance, comparing with those of non-topological changes or unchanged. In Exp2, disks with different amount of holes or similar arcs were used as target stimuli, subjects were required to perform a 2AFC task after a 3s display in which the suppressed figures might be presented in the upper or lower visual field, the detection accuracy were compared, which indicated that the topological changes have a higher chance to be detected during suppression. The result strongly supported Global First in implicit perception, and revealed the high priority of topological properties in human visual processing, meanwhile it suggested the possible subcortical visual processing of topological properties.