Wendt Mike, Klein Stina, Strobach Tilo
Department of Psychology, Faculty of Human Sciences, Medical School HamburgHamburg, Germany.
Front Psychol. 2017 May 10;8:682. doi: 10.3389/fpsyg.2017.00682. eCollection 2017.
In task switching, participants perform trials of task repetitions (i.e., the same task is executed in consecutive trials) and task switches (i.e., different tasks are executed in consecutive trials) and the longer reaction times in switch trials in comparison to these times in repetition trials are referred to as switch costs. These costs are reduced by lengthening of an interval following a cue that indicates the upcoming task; this effect demonstrated effective task preparation. To investigate the role of task switching practice for these preparation effects and task switch costs, we applied a task switching paradigm, involving two digit classification tasks, in six successive practice sessions and varied the length of the preparation interval. To further examine practice-related processing alterations on preparation, particularly concerning the focusing of visual attention and control of response competition, we added an Eriksen flanker task in the initial and the final session. Unlike the two digit tasks, which were always validly cued, the Eriksen flanker task occurred randomly after a cue that indicated one of the other two tasks (i.e., invalid task cuing). The results showed that, in the initial session, task switch costs for the digit tasks were reduced after a long preparation interval but this reduction disappeared after practice. This finding is consistent with the assumption of practice-related enhancement of preparation efficiency concerning non-perceptual task processes. Flanker interference was larger after preparation for a task repetition than for a task switch and (regarding error rates) larger in the final than in the initial session. Possible mechanisms underlying these attentional modulations evoked by task-sequence-dependent preparation and by task switching practice are discussed.
在任务切换中，参与者要进行任务重复试验（即连续试验中执行相同任务）和任务切换试验（即连续试验中执行不同任务），与重复试验中的反应时间相比，切换试验中较长的反应时间被称为切换成本。通过延长提示即将到来任务的线索之后的间隔时间，这些成本会降低；这种效应表明了有效的任务准备。为了研究任务切换练习对这些准备效应和任务切换成本的作用，我们应用了一种任务切换范式，该范式涉及两个数字分类任务，进行了六个连续的练习阶段，并改变了准备间隔的长度。为了进一步研究与练习相关的准备过程中的加工变化，特别是关于视觉注意的聚焦和反应竞争的控制，我们在初始阶段和最后阶段增加了一个埃里克森侧翼任务。与总是有有效提示的两个数字任务不同，埃里克森侧翼任务在提示了其他两个任务之一（即无效任务提示）之后随机出现。结果表明，在初始阶段，经过较长的准备间隔后，数字任务的任务切换成本降低了，但这种降低在练习后消失了。这一发现与关于非感知任务过程的准备效率与练习相关增强的假设一致。与任务重复准备相比，任务切换准备后的侧翼干扰更大，并且（就错误率而言）在最后阶段比在初始阶段更大。我们讨论了由任务序列依赖的准备和任务切换练习引起的这些注意调制的潜在机制。
