Effects of arousal and directed attention on hemispheric asymmetry in a finger-tapping dual-task paradigm.

In the present study we investigated the effects of concurrent verbal (reading) and nonverbal (humming) cognitive tasks on right- and left-hand finger-tapping in relation to hemispheric asymmetry in right- and left-handed females and males. The aim of the study was to investigate effects of attending either to the cognitive or manual task, and effects of differences in arousal attributed to the various tasks. The results revealed decreased finger-tapping frequency in males, and especially in right-handers, during execution of both the reading and humming task. For the reading task, the interference was lateralized, with a greater decrease in tapping frequency in the right hand. No interference was observed in the female groups. Biased attention to the cognitive or manual task did not have any effect on finger-tapping. However, increased arousal was observed during execution of the humming task, thus indicating this to be a mediating factor in finger-tapping interference.