Geng Joy J, Behrmann Marlene
Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Psychol Sci. 2002 Nov;13(6):520-5. doi: 10.1111/1467-9280.00491.
We explored how variability in the probability of target locations affects visual search in normal individuals and in patients with hemispatial neglect, a deficit in attending to the contralesional side of space. Young and elderly normal participants responded faster when targets appeared in the more probable region than when targets appeared in the less probable region. Similarly, patients were sensitive to the distribution of targets, even in the neglected field. Although the attentional gradient that characterizes neglect was not eliminated, the response facilitation due to the probability distribution was proportionate to that of control participants and equal in magnitude across the neglected field. All participants exploited the uneven distribution of targets to enhance task performance without explicit instructions to do so or awareness of biases in their behavior. These results suggest that attentional orientation and sensitivity to external probabilities are possibly dissociable. An early sensory and a late motor mechanism are postulated as possibly being involved in the observed probability-matching behavior of participants.
我们探究了目标位置概率的变异性如何影响正常个体以及患有半侧空间忽视（一种对空间对侧注意缺陷）患者的视觉搜索。当目标出现在概率较高的区域时，年轻和年长的正常参与者的反应速度比目标出现在概率较低的区域时更快。同样，患者对目标分布敏感，即使在被忽视的视野中也是如此。尽管表征忽视的注意梯度并未消除，但由于概率分布导致的反应促进与对照组参与者相当，且在整个被忽视视野中幅度相同。所有参与者都利用目标的不均匀分布来提高任务表现，而无需明确的指示或意识到自身行为中的偏差。这些结果表明，注意定向和对外部概率的敏感性可能是可分离的。假定一种早期感觉机制和一种晚期运动机制可能参与了参与者观察到的概率匹配行为。
