Attentional Control in Vision

当我们凝视一个复杂的视觉场景时，是什么决定了我们看向哪里？目前的理论认为，视觉注意力是由两种不同的机制控制的：“目标导向”时，视觉注意力是面向观察者的目标，和“刺激驱动”时，视觉注意力是“捕获”的对象和事件在外部世界的目标无关。在本研究中要解决的主要问题是，“视觉注意力是否可以被单纯的刺激驱动的方式捕获？“在过去的十年里，大量的经验证据支持至少有一个刺激特征，突然发作，可以驱动注意力。这一证据是使用视觉搜索范式获得的，在这种范式中，一个突然的视觉开始（碰巧是目标）出现在几个“无开始”元素（通常是通过从前面的占位符对象中删除隐藏部分而形成的）中。 相比之下，其他视觉特征，如颜色，亮度，闪烁和运动似乎不能捕捉注意力。 这些发现使人们相信视觉突然出现是一种特殊现象。一种流行的解释是，它们之所以能吸引注意力，是因为它们对应着新的感知对象的出现。 然而，目前的研究寻求另一种解释的证据，在这种解释中，突然的视觉开始可能会引起注意，因为它们对应于视野中最早（和最大）的变化形式。 实际上，对非发病因素的感知是延迟的。 这一假说是有争议的，主要是因为这种说法被认为是不符合传统的时间视觉（涉及一种称为时间整合的现象）。因此，本研究计划的第一阶段是致力于开发一个新的，时间编码帐户的时间整合，是基于人类的心理物理数据从一个新的变化检测范式以及数学建模技术。 此外，还将使用双视呈现范例来尝试将时间编码过程定位在视觉系统内（即，在V1之前或V1之后）。 这项研究的第二阶段将集中在这个时间编码过程是如何受到视觉系统的其他更高层次的状态，如注意力是否集中在一个单一的对象或分散在几个对象（因为它通常是在视觉搜索范式）的影响。 总而言之，本系列实验很重要，因为它们将扩展我们对时间视觉的了解，同时也更彻底地了解为什么突然的视觉爆发在捕捉注意力的能力方面显得独特。

When we gaze at a complex visual scene, what determines where we look? Current theory suggests that visual attention is controlled by two distinct mechanisms: "goal-directed" when visual attention is oriented in terms of the observer's goals, and "stimulus-driven" when visual attention is "captured" by objects and events in the external world irrespective of goals. The primary question that will be addressed in the present research is, "Can visual attention ever be captured in purely stimulus-driven fashion?" Over the past decade, substantial empirical evidence has supported the possiblity that at least one stimlus feature, abrupt onset, can drive attention. This evidence has been obtained using a visual search paradigm in which a single abrupt visual onset (which happens to be the target only by chance) appears among several"no-onset" elements (which are typically formed by removing camouflaging parts from preceding placeholder objects). In contrast, other visual features such as color, luminance, flicker, and motion do not appear capable of capturing attention. Such findings have led to the belief thatabrupt visual onsets are special. One popular interpretation is that they capture attention because they correspond to the appearance of new perceptual objects. However, the present research seeks evidence for an alternative account in which abrupt visual onsets may capture attention because they correspond to the earliest (and largest) form of change in the visual field. What actually happens is that perception of the no-onset elements is delayed. This hypothesis is controversial primarily because such a claim has been thought to be inconsistent with traditional accounts of temporal vision (involving a phenomenon known as temporal integration). Thus, the first phase of this research program is devoted to developing a new, temporal coding account of temporal integration that is based on human psychophysical data obtained from a novel change detection paradigm as well as mathematical modeling techniques. In addition, a dichoptic presentation paradigm will also be used in an attempt to localize the temporal coding process within the visual system (i.e., before V1 or after V1). The second phase of this research will then focus on how this temporal coding process is affected by other higher-level states of the visual system such as whether attention is focused on a single object or divided over several objects (as it typically is in the visual search paradigm). Together, the present series of experiments are important because they will extend our knowledge of temporal vision while also providing a more thorough understanding of why abrupt visual onsets appear unique in their ability to capture attention.