Abstract

The primary objective of the current thesis was to examine age differences in sequential finger tapping with concurrent cognitive tasks of varying levels of difficulty. The first study was designed to determine the point at which age equivalence would be reached on the finger tapping task. Results of Study 1 established age equivalence in sequential tapping after one block of practice. The second study was designed to assess age differences in sequential tapping when combined with a low-load semantic judgment task that had also shown age equivalence under single-task conditions. Despite age equivalences in single-task performance, age differences in fine motor performance emerged when the sequential tapping task was paired with semantic judgments. Older adults had greater dual-task costs than younger adults in both motor measures (accuracy and reaction time). Neither age group incurred cognitive costs. Study 3 was designed to examine the boundary conditions of these results using a within-subjects manipulation of cognitive load. The same sequential tapping task was paired with a mental arithmetic task that had two levels of difficulty. Age differences in motor accuracy were evident in low-load conditions and both age groups had motor and cognitive costs in the high load condition. These results suggest that older adult's resources were already taxed in the low-load condition whereas younger adults' performance only faltered when load was high. Taken together, these results demonstrate that older adults require greater executive control to tap sequentially than younger adults. These results converge with existing simple tapping and gross motor aging research in demonstrating cognitive penetration of motor task performance with age.