A Study On Visual Temporal Grouping

Temporal grouping is the visual process in which the visual system divides the successively presented stimuli into two sub-groups based on the temporal clues. People selectively process either sub-group according to the demand of task. Recent studies have found that temporal grouping can not be maintained while the attention is exhausted by the irrelevant task, indicating that attention is an essential factor in temporal grouping. This result, however, has two probable explanations: One is that temporal grouping requires additional attention. Specifically, it would be interfered due to the deficit of attention while the attention was consumed by the irrelevant task. The other is that temporal grouping does not require additional attention. Temporal grouping for related task would be accomplished automatically while the task is being executed. At this situation, temporal grouping would be interfered as the performance of related task decreased due to the consumption of the attention of the unrelated task.To test these two possibilities, we have conducted experiment that explored whether temporal grouping can be maintained without independent attention using the single task paradigm, in which people are generally believed to be able to focus their attention on the related task. However, the task de facto consumed almost all of the attention resources, and no more attention could be used in temporal grouping. The result suggested that temporal grouping needs independent attention.In addition, we explored whether temporal grouping can be maintained for a relatively long time with enough attention. Experiment 2 and 3 showed that despite adequate attention, the effect of temporal grouping would decay after a while, suggesting that the process of spatial grouping is accomplished at an early stage. These two processes are independent with each other.