认知与发展心理学研究室知识库

人类视觉系统需要实时处理随时间不断变化的外界信息，因此了解视觉注意在时间维度上如何分配对探究人类在动态环境中的信息加工有着重要意义。本论文主要从视觉注意动态分配的内生规律及其与外部信息结构的交互关系入手，来考察视觉注意分配的时空动态特性及其背后的神经机制。

第一部分(第二章)考察了外界信息的时间结构如何影响注意在时间上的分配。结合行为与脑电研究，我们发现，背景节律信息的时间层级结构能够被大脑以神经振荡同步化的方式提取，并通过跨频段调节的方式来组织注意资源在动态信息加工过程中的分配情况。此外，背景节律信息对注意动态分配的调制作用具有一般性和自动化特性:既不局限于某一种特定形式或感觉通道的节律信息，也无需主动注意的参与。该研究揭示了在动态变化的场景中，注意利用外界信息的时间层级结构进行实时选择和信息组织的机制和过程。

第二部分(第三章)从注意内生的动态分配特征出发，考察了在相对连续的二维和三维空间中，视觉注意的时空采样规律。研究结果表明，注意的自发式采样节律具有一定的空间组织结构。具体表现在，不同空间位置上注意采样节律的频率及相位的不同:频率信息反映了注意对不同空间位置的偏好和采样速率的不同，而相位关系则反映了注意在各空间位置之间的采样时序。这些结果在一定程度上揭示了注意内生的时空分配图谱。

第三部分(第四章)着重考察了单眼信息在注意动态分配中所起的作用。我们利用单眼信息在早期视觉通路中独立输入的特性，将连续呈现的刺激序列在两眼之间进行切换。我们发现，眼间切换会在短时程内(约100毫秒)损害之后信息的加工;但如果主动忽略或抑制单眼信息的话，眼间切换反而会促进之后的刺激的加工。这些结果揭示了在早期视觉加工阶段，自上而下的调控在注意动态分配中所起的两重作用:既有单眼注意选择，也可以发生基于单眼的主动抑制。

综上所述，本论文通过以上三方面的研究揭示了人类视觉注意系统如何对连续动态信息进行时空组织。从时间维度来看，注意通过提取外界信息的时间层级结构，从而完成对实时动态信息的层级化组织。从空间维度来看，注意以不同的频率和相位对不同空间位置进行自发采样，从而完成对空间信息的组织编码。我们的研究在一定程度上揭示了这些认知过程的神经基础，并强调了早期视觉加工通路在注意动态分配中的作用。这些研究有助于将来进一步阐明视觉注意分配的时空动态特征及其背后的神经机制。

With dynamic changes over time, information in the external world goes far beyond our mental capacity to scrutinize every bit of it. To surmount this limitation in sensory information processing, we need to reduce the excess and select the most relevant sensory information in surrounding events. In the following series of 3 studies, we investigated how attentional resources are organized and modulated in both space and time.

In the first part, we investigated how temporal regularities contribute to attentional selection during real-time information processing. We superimposed a task-irrelevant rhythm on a rapid visual stream containing two temporally proximate targets. We found the impairment of detecting the second target, known as the attentional blink, can be modulated by the rhythmic context. More importantly, electroencephalographic recordings showed individual differences in neural entrainment of the higher-order structure in contextual rhythms correlate with the magnitude of observed attentional effect. These results altogether indicate human acquires the ability of involuntarily exploiting temporal hierarchy to reframe attentional deployment to dynamic information.

In the second part, we investigated how attentional rhythms spread across multiple locations in a uniform space. Using a detection task with fine temporal resolution, we found the distribution of visual attention is non-uniform but intrinsically organized in both space and time dimensions. The spatial organization of attentional selection is encoded in the phase and frequency of diverse sampling rhythms, providing a new perspective to understand the spatiotemporal map of visual attention.

In the third part, we examined how top-down attention modulated dynamic information processing at monocular-processing level. With visual stream switched from one eye to the other eye, voluntary attention to the first eye caused a delayed attentional switching to the second eye; while explicitly ignoring the content in the first eye increased the accuracy in response to the following information presented in the other eye. These results suggest voluntary suppression can have an effect on dynamic information processing at eye-specific stages of visual processing.

In summary, the results discussed in this dissertation have illustrated how attentional deployment is dynamically organized in both space and time. On one hand,in the time domain, attentional deployment over dynamic information can be recomposed by the temporal structure of contextual rhythms. And on the other hand, in the space domain, the distribution of visual attention is non-uniform but intrinsically organized across space with diverse sampling rhythms. Moreover, we also address the special role that top-down modulation can play in dynamic attending at monocular level. Altogether, these findings shed new light on the issues about spatiotemporal organization of visual attention.