关键词: 时序知觉, 内源性注意, 外源性注意, 知觉组织

Abstract: Perceptual grouping is an important factor affecting temporal order perception. Whereas grouping of perceptual elements to form meaningful objects may occur relatively automatically and independently of top-down attention selection. The effect of perceptual grouping on temporal order perception may occur mainly in the early stage of perceptual processing. It has also been found that exogenous attention and endogenous attention represent two attention systems that can affect temporal order perception. Generally, perceptual judgments are biased towards attended stimuli, which are more likely to be perceived appeared first. A further question concerns whether attention can regulate the effect of perceptual organization on temporal order perception. The goal of the present study was to investigate the role of endogenous and exogenous attention in the effect of perceptual grouping on temporal order perception.
The "C" figure composed of three line segments was used as the experimental material. Participants performed a ternary-response task in which two stimuli were presented in a configuration that encouraged perceptual grouping or not. In the task, the participants were required to report which stimulus was presented first, or else that the two stimuli appeared to have been presented simultaneously. Within-subjects design was conducted in Experiment 1 and Experiment 2, perceptual grouping(one-object and two-object), attention condition (valid cues and invalid cues), and SOA(0ms, ±15ms, ±30ms, ±45ms, ±90ms) as the independent variables, to investigate the role of exogenous and endogenous attention in the effect of perceptual grouping on temporal order perception.
The temporal order judgment response of the subjects was converted into the judgment frequency of the picture on the same side with the cues appeared first and the judgment frequency of two pictures appeared at the same time. The results showed that when endogenous attention cues were used, the judgment frequency of the picture on the same side with the cues appeared first in the effective cue condition was significantly higher than that of the invalid cues condition, while the judgment frequency of simultaneous in the effective cues condition was significantly lower than that of the invalid cues condition. The same results were also found by using exogenous attention cues. However, compared with endogenous attention cues, exogenous attention played a more important role in the effect of perceptual organization on temporal order perception. This may be due to the fact that endogenous attention and exogenous attention speed-up perceptual processing about the stimulus appearing at the attended location, thus destroying the grouping of perceptual elements to form meaningful objects, and reducing the effect of perceptual organization on temporal order perception. However, the effect of endogenous and exogenous attention on temporal order perception was limited. The results show that the frequency of simultaneous judgment of the perceptual grouping condition is significantly higher than the other condition regardless of whether the two figures appeared at the same time. This indicates that even under the influence of attention cues, the perceptual organization process still has an effect on temporal order perception. The mechanism of attention in the influence of perceptual organization on temporal order perception needs to be further studied by cognitive neuroscience technology.

Key words: temporal order perception, endogenous attention, exogenous attention, perceptual grouping