Maintenance and shifting of task-specific sets of stimulus selection in neurologically normal persons and ADHD patients

01.08.2015 bis 30.09.2018

The planned project aims at exploring the cognitive management of task-specific attentional sets in situations associated with varying requirements of stimulus selection. We will focus on executive processes of integrating and coordinating task-specific attentional sets by comparing task-specific stimulus selection processes in task-switching and single-task conditions and assess persistence and preparation of task-specific attentional sets when selection demands change. In this vein, we will investigate behavioral and electrophysiological evidence for strategic adjustments of processing elicited by (both constant and changing) stimulus selection constraints in a currently relevant as well as in a temporarily irrelevant task. To this end, we will pursue different domains of stimulus selection (i.e., visuo-spatial, local/global, temporal). The expected findings will increase our knowledge regarding strategic control of dynamically changing attentional constraints in dual-task situations. Taking into account the increasingly prominent role of attention-related disorders in clinical neuropsychology as well as in everyday life contexts, a substantial part of our project aims at relating these executive processes to chronic attention deficits by correlating our experimental findings with subclinical attention-related symptoms and comparing performance measures in individuals suffering from chronic attention deficits (i.e., attention deficit hyperactivity disorder, ADHD) with control participants without ADHD. The conditions set up in the experiments of the planned project will extend previous research on ADHD by allowing us to examine possible specific impairments in switching between attentional sets in dual-task contexts, such as set perseveration, lack of preparatory set-implementation, or lack of usage of formally irrelevant but contextually useful stimulus information in favor of maintaining attentional focusing (Merkt et al., 2013). Moreover the experiments of the planned project aim to reveal general differences of patients with ADHD and normal control participants in the management of dynamically changing stimulus selection demands, such as the adoption of more similar task-specific attentional sets to reduce switching demands (at the cost of task-specific optimization of stimulus processing) or the efficiency of dealing with stimuli that serve as distractors for a current task but usefully predict stimulus events in a subsequent task. The planned investigations will thus be informative regarding specific impairments or processing strategies of patients with ADHD and might allow us to differentiate subtypes/presentations of ADHD. Identification of processing strategies in ADHD will, in turn, give us the option of introducing experimental manipulations aimed to induce related biases in normal participants and assess the consequences thereof regarding task performance.