The Experimental Research On The Attentional Timing Mechanism Of Visual Information

Time perception, being regarded as perceived present, has a three-second around temporal extent which is underlying the sense of present. Also, it is substrate for temporal integration of informations from which unitary and coherent percepts are established. The range of perceived present represented a basic temporal organization of humans' motion behaviors, as well as providing a temporal window for the activities of conscious information processing.This research, beginning with the definition of time perception based on range-synthetic model, reviewed classical researches on time perception and updated researches related with temporal processing of information. Then, it was suggested that time perception represented the time limits of conscious information processing. Based on this hypothesis, five experiments were designed to explore the timing mechanisms, especially the time limits, of selective attention for visual information processing.Three paradigms, named as spatial search, spatial RSVP search, and standard RSVP search, were used respectively in first three experiments to explore the atttentional timing mechanism underlying visual search. Also, the effects of spatial location (Expt. 1 and 2), search task (Expt. 1), setsize (Expt. 1, 2 and 3), SOA between items (Expt. 2 and 3), and discrimination of items (Expt. 1, 2 and 3) on the performance of visual search were examined. Experiment 4 and 5 both used standard RSVP paradigm with double task to explore the phenomenon called attentional blink (AB). Further, the availability of AB effect under conditions with different target identities, task requirements and presenting durations of items was examined to uncover the attentional timing mechanism of visual information processing.The present research concluded that:Firstly, both parallel and serial component was founded in feature and conjunction search in spatial search paradigm, in which the RT of subjects' performance also increased with the increase of setsize and decrease of discrimination among items.Secondly, the correct ratio of subjects' performance in conjunction search increased with the increase of both SOA and discrimination among items, with higher correct ratios under the target-absent condition, in spatial RSVP search paradigm which reflected dynamic allocation of attention resource in multiple stages of processing.Thirdly, the performance of subjects increased with the increase of SOA and the effect of discrimination was lost because of the masking between items in standard RSVP search paradigm. Also, higher correct ratios under the target-absent condition were argued as reflecting the flexibility of attention processes.Fourthly, the performance of second target (T2) detection was impaired in condition of dual-target task compared with single-target task in the time range of 200 to 400 ms after the onset of first target, in standard RSVP paradigm with double tasks, which represented remarkable attentional blink effect.Fifthly, with the same paradigm, significant AB effect was found under the conditions of different target identity and task requirement, which suggested that this effect represented the attentional timing characteristic of postperceptual and even working memory processing, rather than in the stage of perceptual organization.Sixthly, attentional blink and visual search represented different attentional timing mechanism. The former involved the awareness of two targets and the time limit of attention switching here was estimated as 200 to 400 ms around. The latter, visual search, involved the detection of single target and the speed of attention switching was estimated as 100 to 150 ms per item, which may include the effect of spatial serial processing and overt eye movement, with the index of reaction time. On the other hand, the temporal resolution of attention selection was estimated as 80 to 160 ms per item in the spatially serial search and 160 ms per item in the standard serial search with remarkable masking effects, respectively, both with the index of correct ratio. Lastly, visual search and attentional blink represented more on the bottleneck of early attention selection and of late selection, respectively. Thus, a theory of multi-stage selection was used to integrate the debates between the two fields.Based on the theoretical analysis of the contents of classical time perception studies, the present research demonstrated that time perception in nature represented the time limits of conscious information processing. It may be used to integrate the fields of classical time perception and of temporal processing of information in contemporary cognitive neuroscience. Based on the nature of conscious awareness, the attentional timing was directly studied, which emphasis the limits of attention and even conscious information processing in temporal dimension. Also, an integrated theory of multi-stage was used to indicated that there exist universal but multiple levels of temporal limits, which expanded the studies on time perception and range-synthetic model. The present research also indicated that the attention selection in the time dimension occurred in multiple stages of information processing, which made it possible to integrate debates in visual search and attentional blink. At last, the present research demonstrated it's value by introducing visual search and attentional blink paradigms into field of time perception and using varied experimental designs and indices to explore timing of attention and factors affect it. This last point represented a synthetic research approach with multiple paradigms, multiple methods and multiple factors suggested by range-synthetic model, which will show its vitality in uncovering the nature of time perception.As the end, furth research suggestions were provided based on the deficiencies of present research on the research contents, methods, and so on.