Bonnel A M, Hafter E R
Centre National de la Recherche Scientifique, Marseille, France.
Percept Psychophys. 1998 Feb;60(2):179-90. doi: 10.3758/bf03206027.
Past studies of simultaneous attention to pairs of visual stimuli have used the "dual-task" paradigm to show that identification of the direction of a change in luminance, whether incremental or decremental, is "capacity-limited," while simple detection of these changes is governed by "capacity-free" processes. On the basis of that finding, it has been suggested that the contrast between identification and detection reflects different processes in the sensory periphery, namely the responses of magno- and parvocellular receptors. The present study questions that assertion and investigates the contribution of central processing in resource limitation by applying the dual task to a situation in which one stimulus is auditory and one is visual. The results are much the same as before, with identification demonstrating the tradeoff in performance generally attributed to a limited capacity but detection showing no loss compared with single-task controls. This implies that limitations on resources operate at a central level of processing rather than in the auditory and visual peripheries.
过去关于同时关注成对视觉刺激的研究使用了“双任务”范式，以表明对亮度变化方向的识别，无论是增量还是减量，都是“容量受限”的，而对这些变化的简单检测则由“无容量”过程控制。基于这一发现，有人提出识别与检测之间的对比反映了感觉外周的不同过程，即大细胞和小细胞受体的反应。本研究对这一论断提出质疑，并通过将双任务应用于一种刺激是听觉刺激而另一种是视觉刺激的情况，来研究中央处理在资源限制中的作用。结果与之前大致相同，识别显示出通常归因于有限容量的性能权衡，但与单任务控制相比，检测没有显示出损失。这意味着资源限制发生在中央处理水平，而不是在听觉和视觉外周。
