One cannot simply 'be flexible’: regulating control parameters requires learning

Humans are remarkably efficient at being on task, and flexibly switching back and forth between different tasks. The degree to which they focus on a task, or the extent to which they remain open for switching between tasks, are often considered ‘control parameters’ that are thought to be under parametric control. Theories on cognitive control often assume that people can readily up- or downregulate these control parameters that determine the degree of task focus or switch readiness. Here, we review evidence suggesting that humans are rather inefficient at this parametric regulation of control, as if ‘turning a knob,’ through explicit cues alone. Instead, our research highlights the role of task experience, training, and reward contingencies to cultivate flexible, dynamic adaptations in control parameters.