Response-repetition effects depend on motor set: Evidence for anatomical coding in response selection

Successful motor performance requires a process of response selection that chooses the correct response out of a set of possible ones. Most theories of response selection assume that this selection process operates on spatial codes, which define the location of stimuli and responses in environmental coordinates, with little or no role for the anatomical codes of the effectors involved. In this study, we tested this assumption by investigating response-repetition effects in a response-cuing paradigm using two motor sets (fingers on one hand vs. fingers on two hands). Reaction time results demonstrated a robust response-repetition benefit that was greater for the one-hand set than for the two-hands set. Furthermore, with the one-hand set the repetition benefit was independent of cue type and cue-stimulus interval on the previous trial, whereas with the two-hands set it was strongly modulated by these two factors. These differential response-repetition effects for one- and two-hands motor sets demonstrate the important role of the neuro-anatomical hand distinction in response selection, thereby supporting multiple coding notions.     

Preparing for perception and action (I): the role of grouping in the response-cuing paradigm

Human skilled behavior requires preparatory processes that selectively make sensory and motor systems more efficient for perceiving the upcoming stimulus and performing the correct action. We review the literature concerning these preparatory processes as studied by response-cuing paradigm, and propose a model that accounts for the major findings. According to the Grouping Model, advance or precue information directs a dynamic process of subgroup making-that is, a process of stimulus- and response-set reconfiguration-whereby the internal representation of the task is simplified. The Grouping Model assigns a critical role to the unit of selection, with Gestalt factors and interresponse dependencies mediating the formation and strength of stimulus and response subgroups. In a series of five experiments, we manipulated perceptual and motoric grouping factors, and studied their independent and interactive effects on the pattern of precuing benefits. Generally, the results were consistent with the Grouping Model's account of response-cuing effects.