Mayr Ulrich, Bell Theodor
University of Oregon, OR 97403, USA.
Psychol Sci. 2006 Sep;17(9):774-80. doi: 10.1111/j.1467-9280.2006.01781.x.
The voluntary task-switching paradigm requires subjects to select randomly between tasks and promises to provide a window into executive task selection independent of exogenous influences present in standard task-switching situations. We show here that the degree to which subjects perseverate on tasks across trials captures unique individual differences variance, but also that the switch rate is under strong stimulus-driven control: "Voluntary" switches are much more frequent when the stimulus changes than when it repeats. Most important, we show that individuals whose no-switch trials are selectively slowed exhibit less perseveration and stimulus-driven effects (and thus more voluntary selection) than individuals whose no-switch trials do not show this slowing. We suggest that selective slowing indicates a strategy of treating trials as discrete events--possibly through inhibition of the preceding task set. These results not only demonstrate massive nonvoluntary influences on voluntary selection that are largely untapped by standard task-switching measures, but also show how such influences can be counteracted through strategic adaptations.
自愿任务切换范式要求受试者在任务之间随机选择，并有望提供一个洞察执行任务选择的窗口，该窗口独立于标准任务切换情境中存在的外部影响。我们在此表明，受试者在各次试验中坚持任务的程度捕捉到了独特的个体差异方差，但切换率也受到强烈的刺激驱动控制：当刺激发生变化时，“自愿”切换比刺激重复时更为频繁。最重要的是，我们表明，与无切换试验未出现这种减慢的个体相比，无切换试验被选择性减慢的个体表现出更少的坚持和刺激驱动效应（因此有更多的自愿选择）。我们认为，选择性减慢表明一种将试验视为离散事件的策略——可能是通过抑制先前的任务集。这些结果不仅证明了对自愿选择存在大量未被标准任务切换测量充分挖掘的非自愿影响，还展示了如何通过策略性调整来抵消这些影响。
