In this study, the time-sharing interference paradigm, which involves the concurrent performance of two activities, was used. Subjects performed unimanual tapping (a simple motor task) simultaneously with discrimination of pronounceable four-letter nonwords or sets of four spatially oriented lines (a cognitive task). In addition, two types of instructions, requiring global or local processing, were given to the subjects. Interference was larger with the right unimanual tapping (left hemisphere), and with the performance of the cognitive task during use of the local strategy. The results seem to accord with Kahneman’s theory of limited attentional resources and with the notions of hemispheric specialization and functional cerebral space.