This line of research aims at elucidating the cognitive processes underlying flexible control of behavior. When people switch from one task to another, their cognitive system undergoes a transient state of relative instability that manifests itself in an enhancement of response times and error rates (switch costs). The efficiency of task switches depends on a number of factors. One important aspect is the fate of a recently abandoned task: When switching from one task to the next, the task set of the previously executed task is still highly activated, which may result in massive proactive interference. The control of this interference heavily relies on inhibitory processes (cf. Scheil & Kleinsorge, 2014). A second important factor is based on the way in which information about a forthcoming task switch is presented (cf. Kleinsorge & Apitzsch, 2012). A third important factor consists of the entirety of potential tasks whose performance may be required in a certain situation (cf. Kleinsorge et al., 2004; Kleinsorge & Scheil, 2015a).