Arbuthnott Katherine D
Campion College, University of Regina, Saskatchewan, Canada.
Can J Exp Psychol. 2008 Jun;62(2):91-100. doi: 10.1037/1196-1961.62.2.91.
Asymmetric switch cost, observed when switching between tasks varying in difficulty, shows that the difference between repeat and switch trials is greater when switching to the easier task. Early explanations of this effect attributed this pattern to both positive priming of the difficult task and negative priming of the easier task, but more recent models have focused only on activation processes. The role of inhibition in asymmetric switch cost was examined using backward inhibition, a more direct measure of task-set inhibition. The results indicated asymmetric backward inhibition, with greater sequential inhibition of the easier task (i.e., easy-difficult-easy sequences). Switch costs, however, showed both typical and reversed asymmetry (greater cost when switching from the easy to the difficult task), depending on the relative difficulty of task pairs. This pattern of results indicates that switch costs are attributable to both activation and inhibition processes.
当在难度不同的任务之间进行切换时观察到的不对称切换成本表明，切换到较简单任务时，重复试验和切换试验之间的差异更大。对此效应的早期解释将这种模式归因于困难任务的正启动和简单任务的负启动，但最近的模型只关注激活过程。使用反向抑制（一种更直接的任务集抑制测量方法）来检验抑制在不对称切换成本中的作用。结果表明存在不对称反向抑制，对较简单任务的顺序抑制更强（即简单-困难-简单序列）。然而，切换成本表现出典型和反向的不对称性（从简单任务切换到困难任务时成本更高），这取决于任务对的相对难度。这种结果模式表明，切换成本可归因于激活和抑制过程。
