Lien Mei-Ching, Ruthruff Eric
National Aeronautics and Space Administration Ames Research Center, Moffett Field, CA 94035, USA.
J Exp Psychol Learn Mem Cogn. 2004 May;30(3):697-713. doi: 10.1037/0278-7393.30.3.697.
This study examined how task switching is affected by hierarchical task organization. Traditional task-switching studies, which use a constant temporal and spatial distance between each task element (defined as a stimulus requiring a response), promote a flat task structure. Using this approach, Experiment 1 revealed a large switch cost of 238 ms. In Experiments 2-5, adjacent task elements were grouped temporally and/or spatially (forming an ensemble) to create a hierarchical task organization. Results indicate that the effect of switching at the ensemble level dominated the effect of switching at the element level. Experiments 6 and 7, using an ensemble of 3 task elements, revealed that the element-level switch cost was virtually absent between ensembles but was large within an ensemble. The authors conclude that the element-level task repetition benefit is fragile and can be eliminated in a hierarchical task organization.
本研究考察了任务切换是如何受到分层任务组织影响的。传统的任务切换研究在每个任务元素（定义为需要做出反应的刺激）之间使用恒定的时间和空间距离，从而形成了一种扁平的任务结构。采用这种方法，实验1揭示了238毫秒的巨大切换成本。在实验2 - 5中，相邻的任务元素在时间和/或空间上被分组（形成一个整体）以创建分层任务组织。结果表明，在整体层面上的切换效应主导了在元素层面上的切换效应。实验6和7使用了由3个任务元素组成的整体，结果显示，在不同整体之间，元素层面的切换成本几乎不存在，但在一个整体内部则很大。作者得出结论，元素层面的任务重复益处是脆弱的，并且在分层任务组织中可能会被消除。
