Jonikaitis Donatas, Schubert Torsten, Deubel Heiner
Allgemeine und Experimentelle Psychologie, Ludwig-Maximilians-Universität, München, Germany.
J Vis. 2010 Dec 20;10(14):23. doi: 10.1167/10.14.23.
Dual-task costs are observed when people perform two tasks at the same time. It has been suggested that these costs arise from limitations of movement goal selection when multiple goal-directed movements are made simultaneously. To investigate this, we asked participants to reach and look at different locations while we varied the time between the cues to start the eye and the hand movement between 150 ms and 900 ms. In Experiment 1, participants executed the reach first, and the saccade second, in Experiment 2 the order of the movements was reversed. We observed dual-task costs-participants were slower to start the eye or hand movement if they were planning another movement at that time. In Experiment 3, we investigated whether these dual-task costs were due to limited attentional resources needed to select saccade and reach goal locations. We found that the discrimination of a probe improved at both saccade and reach locations, indicating that attention shifted to both movement goals. Importantly, while we again observed the expected dual-task costs as reflected in movement latencies, there was no apparent delay of the associated attention shifts. Our results rule out attentional goal selection as the causal factor leading to the dual-task costs occurring in eye-hand movements.
当人们同时执行两项任务时，会观察到双重任务成本。有人认为，这些成本源于同时进行多个目标导向运动时运动目标选择的局限性。为了对此进行研究，我们要求参与者在我们将开始眼睛运动和手部运动的提示之间的时间在150毫秒至900毫秒之间变化时，到达并看向不同的位置。在实验1中，参与者先执行伸手动作，然后执行扫视动作；在实验2中，动作顺序相反。我们观察到了双重任务成本——如果参与者当时正在计划另一项运动，他们开始眼睛或手部运动的速度会变慢。在实验3中，我们研究了这些双重任务成本是否是由于选择扫视和伸手目标位置所需的注意力资源有限所致。我们发现，在扫视和伸手位置对探测刺激的辨别都有所改善，这表明注意力转移到了两个运动目标上。重要的是，虽然我们再次观察到了运动潜伏期所反映的预期双重任务成本，但相关注意力转移并没有明显延迟。我们的结果排除了注意力目标选择是导致眼手运动中出现双重任务成本的因果因素。
