Impact of instruction on the acquisition of sequence knowledge in a sensorimotor task

Determining the scope of control underlying the congruency sequence effect: roles of stimulus-response mapping and response mode

Sequential modulation between two task congruencies has been examined to investigate the nature of the cognitive control mechanism underlying the congruency sequence effect (CSE). Previous results regarding what consecutive tasks must have in common to engender the cross-task CSE are inconsistent. The present study examined the roles of stimulus-response (S-R) mappings and response mode as critical factors in determining the scope of control. Two flanker-compatibility tasks having different stimulus and response sets alternated in turn, and the arbitrariness of S-R mappings alone (Experiment 1) or the arbitrariness of stimulus set and the distinctiveness of response modes (Experiment 2) were manipulated. Experiment 1 showed that non-arbitrary S-R mappings engendered a cross-task CSE even when the response modes were different. However, when S-R mappings were arbitrary in Experiment 2, sequential modulation was evident across two tasks only when their response modes were same, irrespective of the arbitrariness of the stimulus set. These results suggest that the arbitrariness of S-R mappings and response mode are salient task features that reconfigure task representation and consequently determine the scope of the control underlying the CSE.

Impact of hand orientation on bimanual finger coordination in an eight-finger tapping task

In the present experiment we examined whether a symmetry tendency in bimanual finger coordination is observable in an experimental setting resembling a serial learning task and whether this tendency is defined in hand-based coordinates. Participants performed an eight-finger bimanual coordination task, in which they responded to sequences of visual stimuli by sequences of tapping movements. Visual stimuli triggered flexion of fingers, which were parallel or mirror symmetrical in respect to the body midline. Additionally, the orientation of the right hand relative to the left hand was varied. When both hands had the same orientation, the mirror symmetrical mode was more stable than the parallel mode. When both hands had different orientations, in contrast, the parallel mode was more stable. This result suggests that the tendency towards mirror symmetry was defined in hand-based coordinates. This outcome is relevant for the research of skill learning regarding the issue of whether acquired sequence knowledge is tied to specific effectors.