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？当前的理论认为，视觉注意由两种不同的机制控制：当视觉注意是根据观察者的目标定向时，是“目标导向”的；当视觉注意被外部世界中的物体和事件“捕获”时，而不考虑目标，则是“刺激驱动”的。这项研究将解决的主要问题是，“视觉注意力能否以纯粹的刺激驱动方式被捕捉到？”在过去的十年里，大量的经验证据支持了这样一种可能性，即至少有一个刺痛特征--突然发作--可以引起人们的注意。这一证据是使用视觉搜索范式获得的，在视觉搜索范式中，单个突然的视觉发作(碰巧是目标)出现在几个“没有发作”的元素中(通常是通过从前面的占位符对象中移除伪装部分形成的)。相比之下，其他视觉特征，如颜色、亮度、闪烁和运动，似乎不能吸引注意力。这些发现让人们相信，突如其来的视觉背景是特殊的。一种流行的解释是，它们吸引了人们的注意，因为它们对应于新的感知对象的出现。然而，目前的研究为另一种说法寻找证据，在这种说法中，突然的视觉开始可能会吸引注意力，因为它们对应于视野中最早(也是最大)形式的变化。实际发生的情况是，对没有发病的元素的感知被推迟了。这一假说是有争议的，主要是因为这样的说法被认为与时间视觉的传统描述不一致(涉及一种被称为时间整合的现象)。因此，这一研究计划的第一阶段致力于开发一种新的时间整合的时间编码帐户，该帐户基于从新的变化检测范式以及数学建模技术获得的人类心理物理数据。此外，还将使用分词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之前或之后)。这项研究的第二阶段将集中于这种时间编码过程如何受到视觉系统的其他高级状态的影响，例如注意力是集中在单个对象上还是分散在几个对象上(就像视觉搜索范例中的典型情况一样)。总之，这一系列的实验很重要，因为它们将扩展我们对时间视觉的知识，同时也提供了对为什么突然的视觉背景在捕捉注意力方面显得独特的更彻底的理解。

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.