The Effect Of Task Maintenance, Task Sets Selection And Response Selection On Mixing Costs

While switch costs has received extensive attention and made substantial progress in recent task-switching research, less progress has been made with regard to the study of mixing costs. Research results from the field of cognitive aging, patients with brain damage, fMRI and ERP reveal that mixing costs and switch costs have different mechanism of task processing and depend on different neural network. More and more researchers believe that mixing costs may be at least as important as an indicator of executive control as switch costs. Conducting the investigations on mixing costs will help to explore the task decision mechanism of adaptive behavior in multi-task situations.This study was focused on the effect of task maintenance, task sets selection and response selection on the mixing cost, and mainly examined the roles of the number of task sets, task sequence and the conflict activated by bivalent stimulus in mixing costs. Three experiments were includes. Experiment 1 controlled the task sets selection of repeated tasks by adding the "colored-cue" situation, in order to investigate whether the additive task maintain affordance in repeat tasks compared with single-tasks attribute to increasing task sets would lead to mixing cost. Experiment 2 was aim to explore the impact of task sets selection and response selection on mixing costs by manipulating the uncertainty of task sequence and the compatibility of "stimulus-response". Experiment 3 led a further study on the uncertainty of task sequence, and wanted to study the influence of the uncertainty of next trial on the performance of present trial.The following conclusions could be drawn from our experiments:(1) Maintain task sets only can lead to mixing costs;(2) Differences in the phase of task sets selection can have effects on mixing costs;(3) Differences in the phase of response selection can have effects on mixingcosts;(4) Uncertainty of the trial N will affect the selection of the trial N-1.Summarily, both task maintenance and task set selection and response selection will affect mixing costs. Task maintenance was associated with the number of tasks. Task sets selection was affected by both the number of tasks and the task sequence, and response selection related to the conflict activated by bivalent stimulus.