Quantitative Analysis of Individual Differences in Visual Attention Properties

本研究的目的是探讨视觉注意的强度和空间范围的个体差异。我们测量了视觉目标在注意和不注意条件下的检测灵敏度。主实验采用双任务和单任务两种范式。在双重任务的条件下，观察员只有在中央任务被正确执行时才做出反应。通过比较这两种情况下的结果，可以估计灵敏度的变化。实验以Gabor图形为刺激，空间频率分别为0.5，1，2，4，8，16 cpd，共10名被试。在主要的实验中，新建造了一个由6个镜子和两个监视器组成的装置，以使观察距离足够长，从而产生精细的光栅。实验结果表明，所有观察者在有中心任务时的空间对比敏感度均低于无中心任务时的空间对比敏感度，这意味着当注意力不集中于目标区域时，检测灵敏度降低。敏感性降低的空间频率特征存在明显的个体差异。这些个体差异分为四种模式。1.灵敏度降低大，在高空间频率中更大，2.灵敏度降低大，没有空间选择性，3.灵敏度降低小，在中间空间频率中更大，4.灵敏度降低小，没有空间频率选择性。

The aim of the present research is to investigate individual differences in the strength and the spatial range of the visual attention. We measured detection sensitivity of a visual target in the conditions with attention and without attention. The double task and the single task paradigms were adopted in the main experiment. In the double task condition the observer responded only when the central task was correctly performed. It was possible to estimate the sensitivity change by comparing the results in these twoconditions. The Gabor pattern was uses as a stimulus and its spatial frequency was set at 0.5,1,2,4,8,and 16 cpd. Ten observers participated in this experiment. In the main experiment an apparatus was newly built which consisted of 6 mirrors and two monitors to make the viewing distance long enough to produce fine gratings. It was possible to measure spatial contrast sensitivity with frequency by using this apparatus.The results show that the spatial contrast sensitivities were found to be lower with the central task than those without the central task for all observers, which means that when attention is not paid to the target area the detection sensitivity decreases. Clear individual differences exist in the spatial frequency characteristics of sensitivity reduction. These individual differences are categorized into four patterns. 1.Large sensitivity reduction, larger in high spatial frequencies, 2.Large sensitivity reduction, no spatial selectivity, 3.Small sensitivity reduction, larger in middle spatial frequencies, 4.Small sensitivity reduction, no spatial frequency selectivity.