认知与发展心理学研究室知识库

     时间是人类存在的基本维度之一。人们的时距知觉经常会受到情绪、注意等因素的调节发生主观扭曲。恐惧作为一种与人类生存密切相关的负性情绪，了解其调节时距知觉的作用机制尤为重要。本研究通过控制恐惧情绪刺激的可预期性，考察恐惧情绪对时距知觉的调节作用及其神经机制。从行为学层面，研究了不同类型的恐惧情绪刺激对间隔时距知觉的调节作用，并通过高时间分辨率的ERPs技术探讨恐惧情绪的可预期性调节间隔时距知觉的神经机制。
    研究一采用IAPS情绪图片考察恐惧情绪刺激对间隔时距知觉的调节作用。其中实验la和实验1b分别采用直接报告法和时间二分法探讨不可预期的恐惧图片对间隔时距知觉的调节作用，结果发现不可预期的恐惧图片条件相比中性图片条件对间隔时距的估计更短;不可预期的高兴图片与中性图片相比对间隔时距知觉的调节作用差异不显著。实验2a和实验2b分别基于区组设计和线索提示设计考察可预期的恐惧刺激对间隔时距知觉的调节作用，结果发现当呈现的情绪图片的类别具有可预期性时，可预期恐惧图片条件下对间隔时距的估计长于中性图片条件，而可预期的高兴图片条件与中性图片条件对间隔时距知觉的调节作用差异不显著。
    研究二采用情绪面孔作为实验材料，探讨社会性恐惧情绪刺激对间隔时距知觉的调节作用。实验3研究不可预期的恐惧面孔对间隔时距知觉的调节作用，发现不可预期的恐惧面孔缩短了间隔时距知觉;实验4和实验5分别研究不可预期的恐惧面孔延迟呈现和前置对于间隔时距知觉的调节作用，结果发现这两者对间隔时距知觉都没有显著性调节作用;实验6考察不可预期的高兴面孔对间隔时距估计的调节作用，结果发现不可预期的高兴面孔与中性面孔相比对间隔时距知觉的调节作用差异不显著;实验7探讨可预期的恐惧面孔将如何调节间隔时距知觉，结果并未发现可预期的恐惧面孔相比中性面孔对间隔时距知觉的调节作用存在显著性差异。以上研究结果说明不可预期的恐惧刺激可能是通过干扰时距加工记忆阶段，导致间隔时距估计缩短。
    研究三采用ERPs技术探讨恐惧刺激调节间隔时距知觉的神经机制，并比较了不可预期(实验8)和可预期(实验9)的恐惧图片相比中性图片调节间隔「距知觉的时间进程，并探讨了不可预期的恐惧刺激对非时距加工任务影响的时间进程(实验10)。结果发现，不可预期和可预期的恐惧图片相比中性图片条件尾诱发了额中区更大的早期注意成分(N1)和更小的特征整合成分(P2)，而不下预期的恐惧刺激对时距知觉的调节作用主要体现在N3成分上，具体表现在图)出现后的200-400毫秒的时间窗口，只有不可预期的恐惧刺激诱发了非单峰的卜成分。时频分析发现相对应的theta节律能量增强，进一步说明了不可预期的p惧刺激干扰了时距加工的记忆阶段，从而导致了间隔时距缩短效应。
    本研究通过一系列行为和脑电研究探讨了恐惧情绪刺激可预期性对间隔时距知觉的调节作用，首次发现了不可预期的恐惧情绪刺激会缩短间隔时距知觉行为和脑电的结果都显示该缩短效应主要发生在时距知觉的记忆阶段而非时汽阶段。本研究丰富和发展了标量计时模型，并深化了对情绪调节时距知觉作用才制的认识。

    Time is a fundamental dimension of human beings' existence. Interval timing perception is often distorted by many factors, such as emotion, attention, etc. As a kind of negative emotion which is closely related to human survival, it is important to understand the mechanisms that how fearful stimuli modulate interval timing. In the present research, by controlling the predictability of fearful stimuli, we investigated the modulation of fearful stimuli on blank interval timing and its neural mechanisms. On the behavioral level, we investigated the modulation of different types of fearful stimuli on interval timing and explored the neural mechanisms of the predictability of fearful stimuli on interval timing using the EEG technique with high temporal resolution.
    In study 1, we used IAPS pictures to explore the effect of fearful stimuli on interval timing. In experiment la and 1b, we used the verbal estimation and temporal bisection paradigms respectively to investigate the effect of unpredictable fearful pictures on interval timing. The results revealed that the unpredictable fearful pictures shortened the interval timing compared with the neutral ones, however, the unpredictable happy pictures did not make significant differences on interval timing compared with the neutral ones. In experiment 2a and 2b, we used the block design and cueing paradigm to investigate the effect of predictable fearful pictures on interval timing. The results revealed that when the fearful pictures were predictable, the subj ective blank interval was lengthened compared with the neutral ones, however, the predictable happy pictures did not make significant differences on interval timing compared with the neutral ones.
    In study 2, we used emotional faces as the materials to explore the effects of social fearful stimuli on interval timing. In experiment 3, we investigated that how the unpredictable fearful faces modulated the interval timing. And it was found that the unpredictable fearful faces  shortened the interval timing.  In experiment 4 and experiment 5, the locations of the unpredictable fearful faces were delayed and prepositioned relative to the blank interval respectively. And we tried to investigate the effect of the above two positions on interval timing. The results revealed that the modulation of unpredictable fearful faces on interval timing was all not significant in above two conditions. In experiment 6, we used unpredictable happy faces to explore the effect of valence of the faces on interval timing. The results revealed that no significant temporal  distortion  effect was  found for unpredictable happy faces compared to the unpredictable neutral ones. In experiment 7, we investigated the effect of the predictable fearful faces on interval timing. And it was found that the predictable fearful faces had no obvious effect on interval timing. The above results supported the hypothesis that the unpredictable fearful faces shortened the interval estimation by interrupting the working memory process of temporal processing.
    In study 3, we used the EEG technique to investigate the neural mechanisms that how fearful stimuli modulate interval timing, and we compared the time course of unpredictable (experiment 8) and predictable (experiment 9) fearful stimuli on interval timing  relative to the  neutral ones. Furthermore, we explored  the effect of unpredictable fearful stimuli in non-timing task (experiment 10). The results suggested that the fearful pictures either in unpredictable or in predictable condition induced larger early attentional component (N1) and smaller feature integration component (P2) in frontal and central regions compared to the unpredictable neutral pictures. However,the modulation of unpredictable fearful stimuli on interval timing was mainly reflected in N3 component. Specifically, in the time window of 200-400 ms after the onset of pictures, only unpredictable fearful picture induced non-single-peaked N3 component.
    The time-frequency analysis results revealed that the frontal theta activities in the above time window increased. This results further illustrated that the unpredictable fear-relevant stimuli may interrupt the memory stage of temporal processing and resulted in the shortening effects.
    Overall，the present study investigated the modulation of the predictability of fearful stimuli on interval timing. And we found that the unpredictable fearful stimuli shortened the subjective interval estimation for the first time. The results of behavioral and EEG experiments all suggested that the shortening effect were generated from the memory stage other than the clock stage of interval timing. This study enriched and developed the scalar expectancy model, and deepened the understanding of neural mechanisms of the modulation of emotion on interval timing.