Schubert T
Institut für Psychologie, Humboldt-Universität Berlin.
Z Exp Psychol. 1996;43(4):625-56.
The aim of this investigation was to analyze dual-task interference in the so called Psychological Refractory Period (PRP) paradigm. In this paradigm subjects have to carry out two choice reaction tasks that overlap in time. A well known result is that reaction time on task 2 (Rt2) increases with decreasing overlap of the two tasks. Thereby reaction time on task 1 is described to be independent of the size of overlap (Rt 1). Usually, this result is explained by the assumption of a PRP which arises in processing of task 2, when serial processing is ongoing in both tasks. It was asked, 1.) whether the PRP is located before or after response selection in the first task and 2.) how the second task influences first task processing. In the experiment subjects had to carry out two choice reaction tasks together. In different conditions the difficulty of response selection in task 2 was systematically increased by varying the number of response alternatives (0, 1, 2, 3). Difficulty of response selection in task 1 was held constant. Overlap between both tasks was varied. This experimental design allows different hypotheses about the sources of interference in both tasks to be examined by use of Schweickert's Critical Path Technique (Schweickert, 1983). Contrary to the results of Karlin and Kestenbaum (1968) the effects of number of response alternatives and size of overlap on Rt2 indicate a localization of the PRP before response selection. The results support models which assume a serial processing in response selection (Welford, 1952). They are contrary to models of parallel processing in this stage (Keele, 1973). The influence of the number of alternatives in task 2 on Rt 1 can be explained by a mechanism of grouping both motor responses.
本研究的目的是分析所谓心理不应期（PRP）范式中的双任务干扰。在该范式中，受试者必须执行两个在时间上重叠的选择反应任务。一个众所周知的结果是，任务2的反应时间（Rt2）会随着两个任务重叠时间的减少而增加。而任务1的反应时间据说是与重叠大小无关的（Rt1）。通常，这一结果是通过假设在两个任务都进行串行处理时，任务2的处理过程中会出现PRP来解释的。研究提出了两个问题：1.）PRP是位于第一个任务的反应选择之前还是之后；2.）第二个任务如何影响第一个任务的处理。在实验中，受试者必须同时执行两个选择反应任务。在不同条件下，通过改变反应选项的数量（0、1、2、3）系统地增加任务2中反应选择的难度。任务1中反应选择的难度保持不变。两个任务之间的重叠时间是变化的。这种实验设计允许使用施韦克尔特的关键路径技术（施韦克尔特，1983）来检验关于两个任务干扰源的不同假设。与卡林和凯斯滕鲍姆（1968）的结果相反，反应选项数量和重叠大小对Rt2的影响表明PRP位于反应选择之前。这些结果支持了假设反应选择中进行串行处理的模型（韦尔福德，1952）。它们与这一阶段的并行处理模型（基尔，1973）相反。任务2中选项数量对Rt1的影响可以通过将两个运动反应分组的机制来解释。
