拓扑性质对视觉新异刺激时距知觉的影响

The Effect of Topological Properties on Duration Perception of Oddball Stimuli

当不被预期的新异刺激出现在重复的标准刺激序列中时,相比标准刺激它的呈现时间往往会被高估,这种现象被称为时距知觉中的新异刺激效应。结合这一现象,本研究考察了对视觉新异刺激时距知觉的高估是否会受到拓扑性质的影响。实验采用新异刺激范式,要求被试比较不同条件下新异刺激与标准刺激的呈现时间,结果发现(1)当标准刺激与新异刺激表现出拓扑性质的差异时,被试更倾向于高估新异刺激的呈现时间;(2)相对于其他几何性质的变化,拓扑性质的变化能够导致更大程度的新异刺激效应。这些结果表明拓扑性质作为一种重要的非时间信息,对视觉新异刺激时距知觉具有重要影响;同时也进一步支持了知觉物体的拓扑学定义。

Previous studies have revealed that the visual system is highly sensitive to topological differences. Topological properties, which are first represented and processed, influence ongoing visual information processing. In addition, as a fundamental human ability, perception of duration can be affected by non-temporal information, including the magnitude, motion, and spatial frequency. Topological properties are another type of important non-temporal information, but little is known whether these can also affect duration perception. Recently, researchers have found that when an unexpected ＂oddball＂ stimulus is embedded in a train of repeated standard stimuli, its duration typically seems to be longer. This phenomenon is termed the oddball effect, and illustrates how duration perception can be affected by stimulus novelty. According to the topological approach to perceptual organization, the core intuitive notion of an object may be characterized precisely as topological invariance, and changes in topological properties will be regarded as the emergence of new objects by the vision system. Therefore, the impact of topological properties on duration perception of oddball stimuli was investigated in this research. In Experiment la 18 participants （7 men, 11 women） were asked to judge whether oddball stimuli （i.e., disks with one or two holes） were longer or shorter in duration than the standard stimuli （i.e., squares with one or two holes）. In Experiment lb, 14 participants （7 men, 7women） rated whether oddballs （i.e., disks with two holes, squares with one hole or squares with three holes）were longer or shorter in duration than standard stimuli （i.e., squares with two holes）. Experiment 2 included 40 participants （15men, 25 women） and was designed to compare effects on duration perception of oddball stimuli between topological properties and other geometric properties. Participants were required to judge whether the oddballs （i.e., parallelograms, trapezoids, circles or rings） were longer or shorter in duration than standard stimuli （i.e., either squares or beeps of 1000 Hz）. Results of Experiment 1 indicated that when there were topological differences between standard stimuli and the oddballs, the magnitude of the oddball effect was significantly larger than that of non-topological differences. Findings from Experiment 2 showed the magnitude of the oddball effect increased monotonically with increasing levels of stability of structural differences between standard stimuli and the oddballs. Compared with other geometrical properties, changes of topological properties induced the largest magnitude of oddball effect. These results suggest that topological properties are one type of important non-temporal information that affect duration perception of oddball stimuli. Furthermore, the current study supports the topological definition of perceptual objects.