Repetition Stimulation Effects On Short Temporal Duration Estimation

The repetition stimulation effect on short temporal duration estimation refers to a phenomenon that the repetition stimulation as the timing target in the time judgment task is perceived longer than the non-repetition stimulation as the timing target. Besides, within a certain frequency range, the higher the frequency of repetition stimulation is, the longer the time of perception is. The repetition stimulation effect was proposed by Treisman and his colleagues, on which they did a lot of research. Studying the repetition stimulation effect on the short temporal duration estimation, researchers usually explain it with the theory of scalar timing model, which was initially proposed by Gibbon and Church (1984). The model presumes that time information processing is involved in three stages:clock, memory and decision. The clock stage is composed of pacemaker, accumulator and switch. Pacemaker can release pulses in specific speed; switch, which is triggered and terminated by the external stimulation, is a mechanism controlled by timing signal with all or none rule, and it is also the inevitable link for pulse to go through pacemaker into accumulator; the accumulator is the mechanism to accumulate the pulse which through the switch and sent by pacemaker. Although the model doesn’t bring the attention processing into timing mechanism outwardly, assumed attention can affect the latency of switch and is able to monitor the transformation of switch between timing processing device and non-timing-processing device. Many researchers attempt to make more reasonable explanations on the repetition stimulation effect on short temporal duration estimation. However, nowadays nobody can tackle the problem. At present there are two theoretical explanations favorable for the cognitive system of the repetition stimulation effect, whose argument lies in whether attention is also a factor about the repetition stimulation effect. some researchers hold that why repetition stimulation has impact on the short temporal duration estimation is that repetition stimulation can increase the speed of the internal clock so as to make people perceive time longer.; while others holds that repetition stimulation effect may not be the only reason for the speed of internal clock, which may also be affected by attention. Because the latency of the switch could change by attention, the effect of repetition stimulation is caused by attention which lengthen the opening latency or shorten the closing latency. These can increase the number of pulses in the accumulator. In accordance to the limitation of previous researches and the ambiguity of the cognitive mechanism, with the multi-way and multi-angle train of thought, this research employs various paradigms and different time ranges to study the cognitive mechanism and neural mechanism of the repetition stimulation effect on short temporal duration estimation deeply and systematically, through three sub-researches including six behavioral experiments and one event-related potential experiment.The research 1 including three experiments is to investigate the repetition stimulation effect on short temporal duration estimation in different time range under the auditory channel. Experiment 1 adopts the interval reproduction task, while standard interval adopting filled tone (No-click) and Click, the reproduction interval stimulus use the filled tone. The results show that the effects of the filled tone and Click on short temporal estimation are different, and the difference is significant. The subjective feeling of Click should be long, and the effect is more obvious with physical temporal interval increasing. Based on the results, experiments 2 uses the temporal generalization task and two ranges of temporal interval (200-800ms,400-1600ms), to investigate the effect of auditory Click on short temporal duration estimation, particularly to explore whether Click can influence the 200-800ms range of short temporal duration estimation. The results show that, whether under the range of 200-800ms or range of 400-1600ms, the filled tone and the Click exert the different influences on short temporal duration estimation in all participants. On the basis of the results of the previous two experiments, experiment 3 further investigate the effect of repetition stimulation on short temporal duration estimation, by using the bisection task with the interval range of 400-1600ms, changing sound stimulus in the learning and testing phase. The results of experiment 3 further prove the stability of repetition stimulation effect on temporal duration estimation. Although the three experiments of the first part use different research approaches and different lengths of temporal interval, the results are more consistent, showing that under the same physical temporal interval, the Click is felt longer than the filled tone, and Click can increase the subject temporal interval.Research 2 including three experiments, on the basis of a series of study results of sub-research 1 and on analysis of sources on repetition stimulation effect, is to investigate gradually the cognitive mechanism of repetition stimulation effect in short temporal duration estimation. Experiment 4 has a preliminary research on the cause of the repetition stimulation effect, by using time bisection task of two ranges of 200-800ms and 400-1600ms. The results show that the switch latency changes couldn’t cause the effect of repetition stimulation on short temporal duration estimation. Experiment 5 uses time reproduction task of break in timing, by varying the temporal interval length, sound stimulus, interrupting position and interrupting time, to continue to explore the cognitive mechanism of repetition stimulation effect on temporal duration estimation. The data analysis shows that attention plays a important role for the effect of repetition stimulation on short temporal duration estimation, and attention is also the important factor of which causes repetition stimulation effects. Attention can control the switch state and produce an oscillation of the switch between the open and closed states. Therefore, experiment 6 also uses the time reproduction task of break in timing, by changing interruption of position and content, to further explore the impact of two mechanisms of interval clock speed and attention on repetition stimulation effect on short temporal duration estimation. The results show that the effect of repetition stimulation on short temporal duration estimation is produced by the two factors of internal clock speed and attention.Research 3 including one ERP experiment, is to investigate brain mechanisms of repetition stimulation effect on temporal duration estimation. Experiment 7 uses event-related potential technologies and draws on ERP research about temporal duration estimation in the past, to investigate the amplitude and latency of ERP component produced by different temporal interval and different stimulus type, and then explore the neural mechanism of repetition stimulation effect on temporal duration estimation. Based on the analysis of ERP data, the results show that the two type temporal interval have shown significant components of ERP, P1,N1, P2, and CNV. Latency peak of PI, in about 50 milliseconds, depends on the stimulus contrast ratio and is also sensitive to the changes of stimulus parameter; N1, in about 100 milliseconds, reflecting the early selective attention in coding processing, is the exogenous composition of ERP induced by stimulus; P2 reflects the perceptual analysis in coding processing, and it is in the encoding processing that P2 reflects the perceptual processing of auditory stimulation and time characteristics. According to the analysis of amplitude and latency of P1, N1, P2, the results showed that two frequency stimulus have not notable effect for them. CNV can reflect the sustained attention for stimulus in encoding processing as well as the psychological load in the decision-making processing. Attention and arousal level are two major factors influencing the amplitude of CNV. After the appearance of positive wave composition P2, two frequency type of temporal interval induce distinct the composition of CNV which will stop rising at about 360ms. Making an repetitive measure analysis of variance of CNV amplitude induced by repetitive stimulus of two frequencies in coding phase, we found that the difference of the CNV amplitudes are significant,and the CNV amplitude induced by high frequency stimulus is greater than that induced by low frequency stimulus. These results provide the neurophysiology proof for the behavioral researches.To sum up, the research explores the effect of repetition stimulation on short temporal duration estimation deeply and systemically with the effective experiment research paradigms and ERP technique. Results show that repetitive stimulations have a significant influence on short temporal duration estimation, and the effect is relatively stable; cognitive mechanism of the repetitive stimulus effect involves the pacemaker in the internal clock as well as the attention which is a key factor; and the effect of repetition stimulation on short temporal duration estimation is relative to the amplitude of CNV. In theory, the research explores the cognitive mechanism about the repetition stimulation on short temporal duration estimation with the theory of the range-synthetic model of time cognition, and proposes the attention switch hypothesis. The hypothesis not only makes up for defects of the previous studies, but also enriches the pervious theories. There are two breakthroughs in method: one is to introduce the research methods in other aspects and overcome the defect that cognitive mechanism cannot be separated in the previous study, on the basis of experimental method of the previous repetitive stimulus effect; the other is that using the comprehensive research method. The research combines the traditional behavioral research with the ERP technology and studies the issues at two different aspects of behavioral research and neurology research. It not only makes up the brain mechanism study on the repetitive stimulation effect of short temporal duration estimation but also provides an idea for the further study of brain mechanism. There are many questions about the repetition stimulation on short temporal duration estimation, further research should be conducted from the aspects of stimulus character, personality variables, influence factor and brain mechanism est. to thoroughly reveal the essence and laws of the repetitive stimulus effect as well as proceed with the time psychology.