Imposed load versus voluntary investment: Executive control and attention management in dual-task performance.

Dual task performance is one of the most frequently used paradigm in the evaluation of coping with concurrent task demands. The Breakfast Task experimented in this paper, was originally developed as a general indicator of coping ability with high demand executive control and attention management requirements. It is a computer-based simulation, in which the performer is required to cook several food items while concurrently setting table for guests. The task was employed in different studies, to compare young to old adults, monolinguals to bilinguals, influence of Parkinson disease and brain injury. However, in a closer examination, it is a dual task setting, in which cooking reflects coping with imposed load while table setting is an indicator of strategy free, voluntary invested effort. Models of workload did not examine the impact of such asymmetric flexibility on concurrent performance. Three experiments with elaborated versions of the breakfast task, show that the difference between the tasks affects concurrent performance formats in response to manipulations of task difficulty, priority change and practice. These results and their implications are discussed in reference to limited capacity, resource and executive control models of multitasking and task load.