Response-response compatibility during bimanual movements: evidence for the conceptual coding of action.

The present study investigated response-response (R-R) compatibility in a bimanual keypressing task. Numeric and spatial stimuli were used to cue responses for each hand. Two groups of participants differed in terms of the stimulus-response mappings for the numeric stimuli. For one group, the numeric stimuli were mapped so that the same number for each hand indicated responses that were anatomically compatible (e.g., index finger of both hands). For the other group, the same number for each hand indicated responses that were left-right compatible (e.g., leftmost finger of both hands). The spatial stimuli were mapped in a spatially compatible manner to the responses for both groups. For numeric stimuli, reaction times (RTs) were faster when the same number indicated the response for each hand, regardless of the mapping. For the spatial stimuli, RTs were determined not only by the pairing of stimuli or responses, but also by how the responses were indicated by numeric stimuli. The results indicate that R-R compatibility effects are mediated by abstract codes that reflect individuals' conceptualizations of their actions.