A major control demand in successful dual-task performance is the task-specific separation of task-goal representations and of the related stimulus-response translation processes. In the present study, we investigated how these cognitive control processes of task shielding are affected by acute psychosocial stress. Fifty-six healthy participants were exposed to either an acute psychosocial stressor (the Trier Social Stress Test) or a standardized control situation prior to a dual task. Task shielding was assessed by analyzing the interference of Task 2 processing on prioritized Task 1 performance. Following successful stress induction, as indicated by increases in salivary α-amylase (sAA) and cortisol that reflect increases in sympathetic nervous system and hypothalamus-pituitary-adrenal (HPA) axis activity, respectively, stressed individuals displayed reduced task shielding relative to controls. This result was further substantiated by a correlation between treatment-related increase in cortisol, but not sAA, and between-task interference, suggesting a potential role of the HPA stress response for the development of the observed effects. As an additional finding, when the volunteers were categorized with regard to their action-state orientation, their orientation did not interact with stress but did reveal generally increased between-task interference, and thus inferior task shielding, for state-oriented as compared to action-oriented individuals. Technical progress during the last decades, particularly in the domains of communication technology and human-machine interactions, has tremendously increased dual-tasking requirements for the individual with regard to both quantity and quality. Similar to dual-tasking, stress has become an omnipresent aspect of modern life, and thus successful performing even under conditions of acute stress represents an everyday demand for more and more individuals. As a consequence, these similar trends are not only indicative of a need to address both issues, but also require an investigation of the specific link between acute stress and dual-task performance; this topic is pursued in the present study. Whenever more than one task is performed at a time, the cognitive system faces additional demands that go beyond those of single-task processing (e.g., online order control, task-set separation, and task-component scheduling). Accordingly, theoretical models of dual-task performance (e.g., Logan & Gordon, 2001;Meyer & Kieras, 1997;Sigman & Dehaene, 2006) assume that simultaneous task performance is coordinated and realized by mechanisms of cognitive control 1 1 It should be noted that this view is not shared by traditional dual-task models. For example, the influential response-selection bottleneck model holds that, due to a structural processing limitation, only certain information processing in two tasks can occur at the same time (e.g., perception and motor execution), whereas other critical stages (e.g., response selection) need to be performed one at a time (i.e., se...
