Maioli C, Benaglio I, Siri S, Sosta K, Cappa S
IRCCS Centro S. Giovanni di Dio - FBF, Via Pilastroni 4, 25125 Brescia, Italy.
Eur J Neurosci. 2001 Jan;13(2):364-72.
We examined timing and scanning paths of eye movements during a visual search task, in which subjects had to detect, as quickly as possible, the presence or absence of a target among distractors [Q-like element among O stimuli (QvsO) and vice-versa (OvsQ)]. According to an influential theory [Treisman, A. & Gelade, G. (1980) Cognitive Psychol, 12, 97--136; Treisman, A. & Sato, S. (1990) J. Exp. Psychol. Hum. Percept. Perform., 16, 459--478], only tasks yielding nonflat search functions (OvsQ) involve focal attention. Alternative models propose that all kinds of visual search are resolved by a biased competitive process, working in parallel across the visual field. Data show that QvsO and OvsQ tasks are characterized by quantitative rather than by qualitative differences in search strategy. No differences between the two tasks were found regarding either the percentage of saccades foveating single stimulus items or the timing of the button response with respect to the onset of the last foveation saccade within a trial. Furthermore, the number of saccades made during search predicted very accurately the time required to accomplish the task and fixation times were independent of the number of stimulus items. On the basis of our results there is no reason to postulate the occurrence of shifts of visuospatial attention, other than those associated with the executions of saccadic eye movements, which are driven by a parallel feature analysis of the visual scene, in both types of search tasks. A time-limited competitive model for attentive target identification, in which both parallel (competitive) and serial (attentive) processing mechanisms are integrated, can account for these findings, providing a unified conceptual framework for all kinds of visual search.
我们研究了视觉搜索任务中眼动的时间和扫描路径，在该任务中，受试者必须尽快在干扰物中检测目标的存在与否[O刺激中的Q样元素（QvsO），反之亦然（OvsQ）]。根据一个有影响力的理论[特雷斯曼，A.和吉拉德，G.（1980年）《认知心理学》，12卷，97 - 136页；特雷斯曼，A.和佐藤，S.（1990年）《实验心理学杂志：人类感知与表现》，16卷，459 - 478页]，只有产生非平坦搜索函数的任务（OvsQ）涉及焦点注意。其他模型提出，所有类型的视觉搜索都通过一个偏向竞争过程来解决，该过程在整个视野中并行工作。数据表明，QvsO和OvsQ任务的特征在于搜索策略上的数量差异而非质量差异。在扫视单个刺激项目的中央凹注视百分比或关于试验中最后一次中央凹注视扫视开始的按钮反应时间方面，未发现这两个任务之间存在差异。此外，搜索过程中进行的扫视次数非常准确地预测了完成任务所需的时间，并且注视时间与刺激项目的数量无关。基于我们的结果，除了与扫视眼动执行相关的那些之外，没有理由假定视觉空间注意转移的发生，在这两种类型的搜索任务中，扫视眼动是由视觉场景的并行特征分析驱动的。一个用于注意力目标识别的限时竞争模型，其中并行（竞争）和串行（注意力）处理机制都被整合，可以解释这些发现，为所有类型的视觉搜索提供一个统一的概念框架。
