Venini Dustin, Remington Roger W, Horstmann Gernot, Becker Stefanie I
The University of Queensland, Brisbane, Australia ; School of Psychology, The University of Queensland, McElwain Building, Brisbane, QLD 4072, Australia.
The University of Queensland, Brisbane, Australia.
J Ophthalmol. 2014;2014:237812. doi: 10.1155/2014/237812. Epub 2014 Jun 3.
In visual search, some fixations are made between stimuli on empty regions, commonly referred to as "centre-of-gravity" fixations (henceforth: COG fixations). Previous studies have shown that observers with task expertise show more COG fixations than novices. This led to the view that COG fixations reflect simultaneous encoding of multiple stimuli, allowing more efficient processing of task-related items. The present study tested whether COG fixations also aid performance in visual search tasks with unfamiliar and abstract stimuli. Moreover, to provide evidence for the multiple-item processing view, we analysed the effects of COG fixations on the number and dwell times of stimulus fixations. The results showed that (1) search efficiency increased with increasing COG fixations even in search for unfamiliar stimuli and in the absence of special higher-order skills, (2) COG fixations reliably reduced the number of stimulus fixations and their dwell times, indicating processing of multiple distractors, and (3) the proportion of COG fixations was dynamically adapted to potential information gain of COG locations. A second experiment showed that COG fixations are diminished when stimulus positions unpredictably vary across trials. Together, the results support the multiple-item processing view, which has important implications for current theories of visual search.
在视觉搜索中，有些注视点落在刺激物之间的空白区域，通常被称为“重心”注视点（以下简称：COG注视点）。先前的研究表明，具有任务专长的观察者比新手表现出更多的COG注视点。这导致了一种观点，即COG注视点反映了对多个刺激物的同时编码，从而能够更高效地处理与任务相关的项目。本研究测试了COG注视点是否也有助于在使用不熟悉和抽象刺激物的视觉搜索任务中的表现。此外，为了为多项目处理观点提供证据，我们分析了COG注视点对刺激物注视点的数量和停留时间的影响。结果表明：（1）即使在搜索不熟悉的刺激物且缺乏特殊高阶技能的情况下，搜索效率也会随着COG注视点数量的增加而提高；（2）COG注视点可靠地减少了刺激物注视点的数量及其停留时间，表明对多个干扰物进行了处理；（3）COG注视点的比例会动态地适应COG位置的潜在信息增益。第二个实验表明，当刺激物位置在各次试验中不可预测地变化时，COG注视点会减少。总之，这些结果支持了多项目处理观点，这对当前的视觉搜索理论具有重要意义。
