Best Virginia, Gallun Frederick J, Ihlefeld Antje, Shinn-Cunningham Barbara G
Hearing Research Center, Boston University, Boston, Massachusetts 02215, USA.
J Acoust Soc Am. 2006 Sep;120(3):1506-16. doi: 10.1121/1.2234849.
If spatial attention acts like a "spotlight," focusing on one location and excluding others, it may be advantageous to have all targets of interest within the same spatial region. This hypothesis was explored using a task where listeners reported keywords from two simultaneous talkers. In Experiment 1, the two talkers were placed symmetrically about the frontal midline with various angular separations. While there was a small performance improvement for moderate separations, the improvement decreased for larger separations. However, the dependency of the relative talker intensities on spatial configuration accounted for these effects. Experiment 2 tested whether spatial separation improved the intelligibility of each source, an effect that could counteract any degradation in performance as sources fell outside the spatial spotlight of attention. In this experiment, intelligibility of individual sources was equalized across configurations by adding masking noise. Under these conditions, the cost of divided listening (the drop in performance when reporting both messages compared to reporting just one) was smaller when the spatial separation was small. These results suggest that spatial separation enhances the intelligibility of individual sources in a competing pair but increases the cost associated with having to process both sources simultaneously, consistent with the attentional spotlight hypothesis.
如果空间注意力像一个“聚光灯”，聚焦于一个位置而排除其他位置，那么将所有感兴趣的目标置于同一空间区域可能是有利的。使用一项任务对这一假设进行了探究，在该任务中，听众要报告来自两个同时说话者的关键词。在实验1中，两个说话者关于额中线对称放置，具有不同的角间距。虽然适度间距时表现有小幅提升，但间距增大时这种提升就减小了。然而，相对说话者强度对空间配置的依赖性解释了这些效应。实验2测试了空间分离是否提高了每个声源的可懂度，这种效应可以抵消声源落在注意力的空间聚光灯之外时性能的任何下降。在这个实验中，通过添加掩蔽噪声使各个声源的可懂度在不同配置下相等。在这些条件下，当空间分离较小时，分听的代价（与只报告一条信息相比，报告两条信息时的性能下降）较小。这些结果表明，空间分离提高了竞争对中单个声源的可懂度，但增加了同时处理两个声源所带来的代价，这与注意力聚光灯假设一致。
