Task frequency influences stimulus-driven effects on task selection during voluntary task switching.
Task frequency influences stimulus-driven effects on task selection during voluntary task switching.
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DOI：
10.3758/s13423-014-0777-0
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发表时间：
2015-08
影响因子：
3.5
通讯作者：
Reiman KM
中科院分区：
文献类型：
--
作者：
Arrington CM;Reiman KM
自愿任务切换过程中的任务选择涉及自上而下、目标导向的机制和自下而上、刺激驱动的机制。改变这两种机制之间平衡的因素尚未得到很好的描述。在当前的研究中，我们研究了任务频率在确定刺激驱动的任务选择程度中所起的作用。两个实验使用了改编自的基本范式，其中刺激可用性的效果充当刺激驱动的任务选择的标志。每次试验中都会出现一个数字和字母，具有不同的刺激起始异步性，并且受试者执行辅音/元音或偶数/奇数判断。在实验 1 中，受试者被告知执行每项任务的相对频率（即 50/50、60/40 或 75/25），并进一步指示他们在任务之间的转换是不可预测的。在实验 2 中，受试者没有得到有关如何选择任务的指示，导致任务频率自然发生变化。无论是指导（实验 1）还是自然发生（实验 2）相对任务频率，执行频率较低的任务都显示出刺激可用性对任务选择的影响更大，这表明刺激驱动机制在任务执行过程中对执行频率较低的任务具有更大的影响。当以目标为导向的任务选择机制不那么频繁地参与时，刺激环境的相对影响就会增加。
Task selection during voluntary task switching involves both top-down, goal-directed and bottom-up, stimulus-driven mechanisms. The factors that shift the balance between these two mechanisms are not well characterized. In the current research, we studied the role that task frequency plays in determining the extent of stimulus-driven task selection. Two experiments used the basic paradigm adapted from, in which the effect of stimulus availability serves as a marker of stimulus-driven task selection. A number and letter appeared on each trial with varying stimulus onset asynchrony and subjects performed either a consonant/vowel or even/odd judgment. In Experiment 1, subjects were instructed as to the relative frequency with which each task was to be performed (i.e. 50/50, 60/40, or 75/25) and were further instructed to make their transitions between tasks unpredictable. In Experiment 2, subjects were given no instructions about how to select tasks, resulting in naturally-occurring variation in task frequency. Both with instructed (Experiment 1) and naturally-occurring (Experiment 2) relative task frequency, the less frequently performed task showed a greater effect of stimulus availability on task selection, suggestive of a larger influence of stimulus-driven mechanisms during task performance for the less frequent task. When goal-directed mechanisms of task choice are engaged less frequently, the relative influence of the stimulus environment increases.