工作记忆的存储时间及目标时距对时间知觉的影响

The Role of Storage Time of Working Memory as well as Duration on Time Perception

本研究操作记忆项消失到时间判断任务开始之间的时间间隔(ISI)和目标时距,探讨工作记忆影响时间判断的灵活性。短的ISI和长的ISI分别在实验1和实验2中完成。被试首先记忆一个客体,然后在每个trial的最后判断探测刺激与记忆项是否相同;在延迟阶段,被试完成时间判断任务,即判断相继出现的两个刺激的时距哪个更长(或更短)。时间任务中的一个刺激与记忆内容完全相同,相应的另一个刺激与记忆内容在形状和颜色上都不同。知觉重复作为控制条件,被试忽略第一个刺激,仅完成时间判断任务。结果发现,时间间隔(ISI)短时,记忆匹配条件下的准确率更高,匹配刺激延长了知觉的时间;但随着时间间隔的增加,工作记忆匹配对时间判断的影响消失。并且,目标时距长时,记忆匹配反而缩短了知觉的时间,这与ISI的长短以及是否有记忆任务无关。研究说明工作记忆对时间判断的影响具有灵活性,与注意的聚焦及注意资源的分配有关。

Time perception has been shown to be influenced by the attentional guidance from working memory （WM）with a stimulus matching the working memory content being judged to last longer than a mismatching stimulus. However, the guidance effect might be complex, modulated by other factors, such as experimental materials as well as task sets. When the interstimulus interval （ISI） between the offset of the memory item and the onset of time perception is long enough, will the attentional guidance based on WM content still occur？ In this study, we combined the change detection task paradigm and the time comparison task to exam the influence of ISI and target duration on time judgment. Participants were asked to memorize an abstract object （both the color and shape） for a subsequent memory test in which they indicated whether a test object changed. During the delay period, participants had to judge which one of the two successive objects was presented longer or shorter, with one object matching the WM item while the other did not. Mere observation without the WM demand was taken as a control task to exclude the contribution of repetition. We manipulated the shorter ISI and long ISI in Experiment 1 and Experiment 2 respectively. Three-way repeated measures ANOVA examined group （WM task, mere repetition）~distractor item （match, mismatch） ×duration （500, 600, 650, 750 ms）, and group was a between-subject factor. The results showed that when the ISI was shorter （Experiment 1）, time judgment accuracy was .72 ±.02 and .67 ± .02 for matching and mismatching condition. However, the difference was not significant in mere repetition group （p 〉 .05）.The triple interaction analysis showed that in WM group, when the duration was shorter （500 ms, 600 ms, 650 ms and 750 ms）, memory-matching stimuli facilitated duration judgment accuracy, whereas when the duration increased 750 ms, the accuracy became worse for memory-matching stimuli than memory-mismatching stimuli （.60 ± .05 vs..76 ± .05）. When the ISI was longer （Experiment 2）, neither the main effect of group nor the main effect of distractor item reached significance （p 〉 .05）. This study suggests that the effect of visual working memory on time judgment is flexible, and is modulated by the interstimulus interval as well as the target duration to be perceived. The variability of object working memory on timing tasks might be related to the focus and allocation of attention.