Nicholls M E, Bradshaw J L, Mattingley J B
Department of Psychology, University of Melbourne, Australia.
Brain Cogn. 2001 Jun-Jul;46(1-2):219-23. doi: 10.1016/s0278-2626(01)80070-1.
Strong leftward perceptual biases have been reported for the selection of the darker of two left/right mirror-reversed luminance gradients under free-viewing conditions. This study investigated the effect of unilateral hemispheric activation on this leftward bias in two groups of dextrals (N = 52 and N = 24). In Experiment 1, activation was manipulated by asking participants to tap with their left or right fingers along their midline. In Experiment 2, participants clenched their left or right hands in their respective hemispaces. Participants selected the stimulus that was darker on the left-hand side 73% of the time. Despite manipulations of activation strength and hemispace, activation had no effect on the asymmetry. If activation was important, the leftward bias should have been enhanced when the left hand/right hemisphere was active and reduced (or reversed) when the right hand/left hemisphere was active. The contribution of left-to-right scanning biases to free-viewing perceptual asymmetries is discussed as an alternative.
据报道，在自由观看条件下，对于两个左右镜像反转的亮度梯度中较暗的那个进行选择时，存在强烈的向左感知偏差。本研究调查了单侧半球激活对两组右利手者（N = 52和N = 24）这种向左偏差的影响。在实验1中，通过要求参与者用左手或右手沿着中线轻敲来操纵激活。在实验2中，参与者在各自的半空间中握紧左手或右手。参与者73%的时间选择左手边较暗的刺激。尽管对激活强度和半空间进行了操纵，但激活对不对称性没有影响。如果激活很重要，那么当左手/右半球活跃时，向左偏差应该会增强，而当右手/左半球活跃时，向左偏差应该会减弱（或反转）。作为一种替代解释，讨论了从左到右的扫描偏差对自由观看感知不对称性的贡献。
