Naefgen Christoph, Janczyk Markus
Department of Psychology, Eberhard Karls University of Tübingen, Schleichstraße 4, 72076, Tübingen, Germany.
Cogn Process. 2019 Feb;20(1):73-85. doi: 10.1007/s10339-018-0887-0. Epub 2018 Oct 10.
In dual-task situations, mutual interference phenomena are often observed. One particularly interesting example of such phenomena is that even Task 1 performance is improved if Task 2 requires a compatible (e.g., both responses are given on the left side) instead of an incompatible response (e.g., one response is given on the right side, and the other on the left side). This is called the compatibility-based backward crosstalk effect (BCE). In a previous paper, we observed support for a critical role of stimulus-response (S-R) links in causing this effect: The BCE was smaller when one of the two tasks was a free choice task. However, an alternative explanation for this observation is that free choice tasks lead to immediate conflict adaptation, thereby reducing the interference from the other task. In the present two experiments, we tested this explanation by varying the amount of conflict assumed to be induced by a free choice task either sequentially (Exp. 1) or block-wise (Exp. 2). While we replicated a sequential modulation of the BCE with two forced choice tasks, we observed (1) no reduction of the BCE induced by (compatible) free choice trials nor (2) an effect of block-wise manipulations of the frequency of free choice trials on the size of the BCE. Thus, while the BCE is sensitive to sequential modulations induced by the (in)compatibility of two forced choice responses, which might point to conflict adaptation, the reduced BCE in dual-task situations involving a free choice task is likely due to its weaker S-R links.
在双任务情境中，常常会观察到相互干扰现象。这类现象一个特别有趣的例子是，如果任务2需要兼容反应（例如，两个反应都在左侧做出）而非不兼容反应（例如，一个反应在右侧做出，另一个在左侧做出），那么即使任务1的表现也会得到改善。这被称为基于兼容性的反向串扰效应（BCE）。在之前的一篇论文中，我们观察到刺激-反应（S-R）联系在引发这种效应中起到关键作用：当两个任务之一是自由选择任务时，BCE较小。然而，对这一观察结果的另一种解释是，自由选择任务会导致即时冲突适应，从而减少来自另一个任务的干扰。在当前的两个实验中，我们通过依次（实验1）或逐块（实验2）改变假定由自由选择任务引发的冲突量来检验这一解释。虽然我们用两个强制选择任务重复了BCE的顺序调制，但我们观察到：（1）由（兼容的）自由选择试验引发的BCE没有减少，以及（2）自由选择试验频率的逐块操作对BCE大小没有影响。因此，虽然BCE对由两个强制选择反应的（不）兼容性引发的顺序调制敏感，这可能指向冲突适应，但在涉及自由选择任务的双任务情境中BCE的降低可能是由于其较弱的S-R联系。
