Ghorashi Shahab, Spalek Thomas M, Enns James T, Di Lollo Vincent
Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC V6T1Z4, Canada.
Atten Percept Psychophys. 2009 Aug;71(6):1233-40. doi: 10.3758/APP.71.6.1233.
Visual search for a target involves two processes: spatial selection and identity extraction. Ghorashi, Enns, and Di Lollo (2008) found these processes to be independent and surmised that they were carried out along distinct visual pathways: dorsal and ventral, respectively. The two experiments that are described in the present article evaluated this hypothesis. Attentional-blink methodology was combined with voluntary spatial cuing in a visual search task: Intertarget lag was used to manipulate identity extraction; predictive cues were used to signal target locations. Central digit cues in Experiment 1 required participants to identify digits before voluntarily directing attention to a corresponding location, whereas flashed dots in Experiment 2 (indicating an opposite location) required attentional redeployment without prior cue identification. Consistent with the dual-pathway hypothesis, cuing was impaired only when the first target and the number cue competed for ventral-pathway mechanisms. Collectively, the results support the dual-pathway account of the separability of spatial selection and identity extraction.
空间选择和身份提取。戈拉希、恩斯和迪洛洛（2008年）发现这些过程是相互独立的，并推测它们分别沿着不同的视觉通路进行：背侧通路和腹侧通路。本文描述的两个实验对这一假设进行了评估。在视觉搜索任务中，将注意瞬脱方法与自主空间线索提示相结合：目标间延迟用于操纵身份提取；预测性线索用于指示目标位置。实验1中的中央数字线索要求参与者在自主将注意力导向相应位置之前识别数字，而实验2中的闪烁点（指示相反位置）则要求在没有事先线索识别的情况下重新部署注意力。与双通路假设一致，只有当第一个目标和数字线索竞争腹侧通路机制时，线索提示才会受损。总体而言，这些结果支持了空间选择和身份提取可分离性的双通路解释。
