Spatial attention in motion perception

注意加工的心理物理学研究使用了几种基于运动知觉的程序，即视觉搜索、线运动错觉和运动后效应。在视觉搜索实验中，我们在一个视野内同时引入了一阶和二阶运动块，并要求受试者从干扰刺激中检测目标块(一阶或二阶运动刺激)。一阶和二阶刺激分别指示亮度定义的和对比度定义的运动刺激。结果表明，一阶运动可以独立并行加工，而二阶刺激不能独立并行加工。在线运动研究中，我们发现被动注意(自下而上注意)和主动注意(自上而下注意)分别在早期至100ms和后期至几秒内独立运行。在运动后效应研究中，我们采用了时间和空间频率固定的正弦移位光栅图案。受试者被要求观看图案一段时间，然后停止移动图案，并观察效果后的运动反转方向。数据表明，额外的需要注意的平行任务降低了后效的程度。因此，我们发现注意加工对后效的持续时间有影响。

Psychophysical study of attentional processing was done using several motion-perception based procedures, i.e., visual search, line-motion illusion, and motion after effect. In visual search experiment, we introduced first-and second-order motion patches together within a field of vision, and asked the subject to detect target patch (either first- or second-order motion stimulus) among distrator stimuli. The firs-order and second-order stimulus each indicates luminance-defined and contrast-defined motion stimulus, respectively. The results suggest the independent parallel processing for first-order motion but not for second-order stimulus. In line-motion study, we found passive attention (bottom-up attention) and active attention (top-down attention) operated independently in an early period up to 100ms and later period up to several seconds, respectively. In motion after effect study, we employed sinusoidally shifting grating pattern with fixed temporal and spatial frequency. Subject was asked to watch the pattern for some time, then the moving pattern was stopped and observing motion after effect to reverse direction. The data suggest that additional attention-demanding parallel task decreased the magnitude of after effect. Thus we found attentional processing influences on the duration of after effect.