Eckstein Miguel P, Pham Binh T, Shimozaki Steven S
Vision and Image Understanding Laboratory, Department of Psychology, University of California, Santa Barbara, CA 93106, USA.
Vision Res. 2004 Jun;44(12):1193-207. doi: 10.1016/j.visres.2003.10.026.
Human performance during visual search typically improves when spatial cues indicate the possible target locations. In many instances, the performance improvement is quantitatively predicted by a Bayesian or quasi-Bayesian observer in which visual attention simply selects the information at the cued locations without changing the quality of processing or sensitivity and ignores the information at the uncued locations. Aside from the general good agreement between the effect of the cue on model and human performance, there has been little independent confirmation that humans are effectively selecting the relevant information. In this study, we used the classification image technique to assess the effectiveness of spatial cues in the attentional selection of relevant locations and suppression of irrelevant locations indicated by spatial cues. Observers searched for a bright target among dimmer distractors that might appear (with 50% probability) in one of eight locations in visual white noise. The possible target location was indicated using a 100% valid box cue or seven 100% invalid box cues in which the only potential target locations was uncued. For both conditions, we found statistically significant perceptual templates shaped as differences of Gaussians at the relevant locations with no perceptual templates at the irrelevant locations. We did not find statistical significant differences between the shapes of the inferred perceptual templates for the 100% valid and 100% invalid cues conditions. The results confirm the idea that during search visual attention allows the observer to effectively select relevant information and ignore irrelevant information. The results for the 100% invalid cues condition suggests that the selection process is not drawn automatically to the cue but can be under the observers' voluntary control.
当空间线索指示可能的目标位置时，视觉搜索过程中的人类表现通常会提高。在许多情况下，贝叶斯或准贝叶斯观察者可以定量预测表现的提高，其中视觉注意力只是简单地选择线索位置处的信息，而不改变处理质量或敏感度，并忽略非线索位置处的信息。除了线索对模型和人类表现的影响之间总体上有很好的一致性外，几乎没有独立的证据证实人类有效地选择了相关信息。在本研究中，我们使用分类图像技术来评估空间线索在注意力选择相关位置和抑制空间线索指示的无关位置方面的有效性。观察者在视觉白噪声中八个位置之一（概率为50%）可能出现的较暗干扰物中搜索一个明亮目标。使用100%有效的方框线索或七个100%无效的方框线索来指示可能的目标位置，其中唯一潜在的目标位置没有线索。对于这两种情况，我们发现在相关位置有统计上显著的、形状为高斯差分的感知模板，而在无关位置没有感知模板。我们没有发现100%有效线索条件和100%无效线索条件下推断的感知模板形状之间存在统计上的显著差异。结果证实了这样一种观点，即在搜索过程中，视觉注意力使观察者能够有效地选择相关信息并忽略无关信息。100%无效线索条件的结果表明，选择过程不是自动被线索吸引，而是可以由观察者自愿控制。
