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Rangelov, Dragan; Töllner, Thomas; Müller, Hermann J.; Zehetleitner, Michael (September 2013): What are task-sets: a single, integrated representation or a collection of multiple control representations? In: Frontiers in human neuroscience, Vol. 7, 524
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Abstract

Performing two randomly alternating tasks typically results in higher reaction times (RTs) following a task switch, relative to a task repetition. These task switch costs (TSC) reflect processes of switching between control settings for different tasks. Thepresentstudyinvestigatedwhethertasksetsoperateasasingle, integrated representation or as an agglomeration of relatively independent components. In a cued task switch paradigm, target detection (present/absent) and discrimination (blue/green/right-/left-tilted) tasks alternated randomly across trials. The target was either a color or an orientation singleton among homogeneous distractors. Across two trials, the task and target-defining dimension repeated or changed randomly. For task switch trials, agglomerated task set spredicta difference between dimension changes and repetitions: joint task and dimension switches require full tasks etre configuration, while dimension repetitions permitre using some control settings from the previous trial. By contrast, integrated task sets always require full switches, predicting dimension repetition effects(DREs) to be absent across task switches. RT analyses showed significant DRE sacross task switches as well as repetitions supporting the notion of agglomerated task sets. Additionally, two event related potentials( ERP) were analyzed: the Posterior-Contralateral- Negativity (PCN) indexing spatial selection dynamics, and the Sustained-Posterior-Contralateral-Negativity (SPCN) indexing post-selective perceptual/semantic analysis. Significant DREs across task switches were observed for both the PCN and SPCN components. Together, DREs across task switches for RTs and two functionally distinct ERP components suggest that reusing control settings across different tasks is possible. The results thus support the'' agglomerated-task-set'' hypothesis, and are inconsistent with'' integrated task sets.''