Quantitative Analysis of Individual Differences in Visual Attention Properties

本研究的目的是探讨视觉注意强度和空间范围的个体差异。我们测量了有注意和无注意条件下视觉目标的检测灵敏度。主实验采用双任务范式和单任务范式。在双重任务条件下，只有当中心任务被正确执行时，观察者才会做出反应。通过比较这两种条件下的结果，可以估计灵敏度的变化。Gabor模式作为刺激，其空间频率分别为0.5、1、2、4、8和16 cpd。10名观察员参加了这个实验。在主实验中，我们新建了一个由6个反射镜和2个监视器组成的装置，使观测距离足够长，可以产生精细的光栅。利用该仪器可以测量空间对比灵敏度与频率的关系。结果表明：所有观测者在有中心任务时的空间对比灵敏度都低于无中心任务时的空间对比灵敏度，即当不注意目标区域时，探测灵敏度降低。灵敏度降低的空间频率特征存在明显的个体差异。这些个体差异可分为四种模式。1.灵敏度降低大，在高空间频率下更大；2 .灵敏度降低大，无空间选择性；4.灵敏度降低幅度小，中频灵敏度降低幅度较大。灵敏度降低小，无空间频率选择性。

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.