Top-down modulation of attentional capture in vision: Electrophysiological investigations

想象一下，你站在一个繁忙的忙碌候机楼里，在登机牌上浏览你的航班信息。当你注意到董事会，其他感官信息，如视觉和声音的人经过，或广播系统的公告，将在很大程度上被忽视。有意地（或“内源性地”）将注意力引导到特定的物体或事件上，使我们能够选择性地忽略与我们当前意图无关的其他感官信息。内源性注意力在日常生活中很明显--它塑造了我们的感知体验，使我们能够处理复杂的多感官世界。如果没有它，世界将是一片“繁花盛开、嗡嗡作响的混乱”（威廉·詹姆斯）。然而，内源性注意控制有时会被外部事件打断。即使在浏览登机牌时，你的注意力也会被突然的、非常突出的或意想不到的刺激所转移，比如一道闪光或一声枪响。这些事件被认为是不自觉地或“外源地”吸引注意力的。注意力的内源性控制和外源性捕获之间的这种区别对于我们理解我们如何与外部世界互动至关重要。在许多情况下，我们负责我们的感官知觉经验的内容，但有时世界上的事件决定了我们所意识到的。直到最近，内源性注意力和外源性注意力在功能和解剖学上都有明显的区别。然而，最近的证据表明，显著视觉刺激（如一个独特的红色项目中的许多均匀的绿色刺激）的注意捕获是不是真的“外生性”，但实际上是由当前的意图控制。换句话说，外部世界永远不会完全控制我们的感知经验，这也总是由与我们相关的东西决定的。虽然当注意力被有意地集中在其他地方时，显著事件是否以及在什么条件下被注意到的问题对感知和认知理论很重要，但它在很大程度上仍然没有得到解决。这是因为以前对这一问题的研究主要采用行为业绩衡量标准，这似乎不足以提供明确的答案。在本项目中，我们将使用注意力捕获的电生理标记，可以在实验任务中从EEG头皮电极非侵入性地获得。这些标记反映了大脑过程的活动，这些大脑过程是以毫秒为基础的注意力选择过程，并将用于发现显着的视觉刺激何时以及如何以纯粹的外源方式捕获观察者的注意力。我们将记录这样的标记，而参与者进行视觉选择任务，其中的任务相关性的显着的视觉刺激，连同不太显着的背景刺激被操纵，以找出是否以及如何注意力捕获介导的有意控制。这个项目的目的是提供新的见解，感觉和意图如何相互作用，创造知觉经验。从应用的角度来看，结果也将有重要的影响，例如，相对于用户界面和复杂的控制系统的设计。在嘈杂的环境（如机场航站楼）中，增加重要视觉信号的可感知性的努力可能必须考虑这样的发现，即这些信号捕获注意力的能力不仅仅取决于它们自下而上的显著性，而且还取决于当前的有意上下文。

Imagine standing in a busy airport terminal scanning the departure board for information about your flight. While you attend to the board, other sensory information such as the sight and sound of people passing by, or announcements from the PA system, will go largely unnoticed. Directing attention intentionally (or 'endogenously') to specific objects or events enables us to selectively ignore other sensory information that is irrelevant to our current intentions. Endogenous attention is manifest in everyday life - it shapes our perceptual experience and allows us to deal with a complex multisensory world. Without it the world would be a 'blooming, buzzing confusion' (William James). However, endogenous attentional control is sometimes interrupted by external events. Even while scanning the departure board, your attention will be diverted by abrupt, highly salient, or unexpected stimuli, such as a flash of light or a gunshot. Such events are said to capture attention involuntarily, or 'exogenously'. This distinction between the endogenous control and the exogenous capture of attention is fundamental for our understanding of how we interact with the external world. In many cases, we are in charge of the contents of our sensory-perceptual experience, but sometimes events in the world dictate what we become aware of. Until recently, it seemed obvious that endogenous and exogenous attention represent functionally and anatomically distinct modes of attention. However, recent evidence has suggested that attentional capture by salient visual stimuli (such as a unique red item among many uniformly green stimuli) is not really 'exogenous', but is in fact controlled by current intentions. In other words, the external world is never completely in control of our perceptual experience, which is always also determined by what is relevant to us. Although the question whether and under which conditions salient events get noticed when attention is intentionally focused elsewhere is important for theories of perception and cognition, it remains largely unresolved. This is due to the fact that previous research on this issue has used mainly behavioural performance measures, which appear insufficient to provide clear-cut answers. In the present project, we will use electrophysiological markers of attentional capture that can be obtained non-invasively from EEG scalp electrodes during experimental tasks. These markers reflect the activity of brain processes underlying attentional selection processes on a millisecond-by-millisecond basis, and will be used to discover when and how salient visual stimuli will capture observers' attention in a purely exogenous fashion. We will record such markers while participants that perform visual selection tasks where the task relevance of salient visual stimuli that are presented together with less salient background stimuli is manipulated in order to find out whether and how attentional capture is mediated by intentional control. The aim of this project is to provide new insights into how sensation and intention interact to create perceptual experience. Results will also have important implications from an applied perspective, for example with respect to the design of user interfaces and complex control systems. Efforts to increase the noticeability of important visual signals in noisy environments (such as airport terminals) may have to consider the finding that the capacity of such signals to capture attention is not simply determined by their bottom-up saliency, but also by the current intentional context.