title: Two Simon tasks with different sources of conflict: an ERP study of motion- and location-based compatibility effects.
abstract: Behavioral and electrophysiological correlates of two Simon tasks were examined using comparable stimuli but different task-irrelevant and conflict-inducing stimulus features. Whereas target shape was always the task-relevant stimulus attribute, either target location (location-based task) or motion direction within the target stimuli (motion-based task) was used as a source of conflict. Data from ten healthy participants who performed both tasks are presented. In the motion-based task the incompatible condition showed smaller P300 amplitudes at Pz than the compatible condition and the location-based task yielded a trend towards a reduced P300 amplitude in the incompatible condition. For both tasks, no P300 latency differences between the conditions were found at Pz. The results suggest that the motion-based task elicits behavioral and electrophysiological effects comparable with regular Simon tasks. As all stimuli in the motion-based Simon task were presented centrally the present data strongly argue against the attention-shifting account as an explanatory approach.
authors.affiliation: Department of Neuropsychology/Behavioral Neurobiology, Center for Cognitive Sciences (ZKW), University of Bremen-Cognium Building, Bremen, Germany. galashan@uni-bremen.de
authors.forename: Daniela
authors.initials: D
authors.lastname: Galashan
authors.forename: Matthias
authors.initials: M
authors.lastname: Wittfoth
authors.forename: Thorsten
authors.initials: T
authors.lastname: Fehr
authors.forename: Manfred
authors.initials: M
authors.lastname: Herrmann
mesh_terms: D000328:Adult; D003220:Conflict, Psychological; D004569:Electroencephalography; D018913:Event-Related Potentials, P300 / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology; D013028:Space Perception / Q000502:physiology*