It’s actually called mixing cost? If a task is a room (a task has a context), two tasks (two contexts) is two rooms, and two tasks performed simultaneously is passing back and forth between two rooms.. the vestibule or path between the rooms will having a mixing of the two rooms – at least the air and lighting.
The Mixing Cost as a Measure of Cognitive Control
This chapter is concerned with how people can maintain task set in a context of changeable demands, avoiding distraction and maintaining their concentration through time. Research shows that continuously repeating the same task over some period of time requires less concentration than repeating the same task in a context in which task switches also occur. The presence of task switches encourages a state of heightened vigilance or surveillance that not only influences switch trials but also affects task repetitions, typically producing a slowing of reaction times compared with the pure repetition context. This effect has been termed the mixing cost. The chapter shows how mixing cost can be used to investigate the mechanisms that promote sustained concentration on task goals. It reviews the main empirical findings on the mixing cost and suggests ideas for further theoretical development.