Task switching (psychology)

Task switching is an experimental research paradigm frequently used in cognitive and experimental psychology. It is mainly used to investigate executive functions.

Basic Structure

Although different versions of the task switching paradigm exist, they all share some common underlying structure. In Task Switching experiments, participants are presented with a series of stimuli, one at a time, and are required to alternate between two different types of tasks that can be performed over the stimuli. For instance, stimuli might be integer numbers in the range 1-9, and the different tasks consist in categorizing the number as even/odd (Task 1), or indicating whether they as smaller or larger than 5 (Task 2).

Variants of the Task Switching paradigm differ on how participants are instructed to alternate between the two tasks. In some experiment, participants might be explicitly instructed to alternate regularly (i.e., every two stimuli) between the two tasks. Alternatively, a task cue that indicate which task should be performed can be provided before the next stimulus, or block of stimuli

The Switch Cost

The most important finding is that trials immediately following a task change take longer that trials where the same task is repeated. This increased latency is known as the switch cost. Various accounts of the switch cost have been proposed. Some authors argue that the switch it is due to an active effort spent in reconfiguring the mental operations ("task set") that one is about of perform. As such, task switching reflects a fundamental operation of cognitive control. Other authors have stressed the importance of the cost payed by inhibiting the set of response associated with the previous task Still others have suggested that the switch cost is just the lack of benefit from a task repetition.