Dissecting the response in response-effect compatibility.

Voluntary actions are guided by sensory anticipations of body-related as well as environment-related action effects. Even though action effects in the environment typically resemble the action goal proper, anticipations of body-related effects can cause interference if they do not correspond to intended environment-related effects. The present study explored which specific response features cause such interference: the spatial location of the moving limb or its anatomical connection to the body causes such interference? Using a response-effect compatibility design with normal and crossed hand-key mappings, we show that environment-related effects are predominantly related to spatial rather than anatomical response features, ensuring that goal-directed behavior is flexible and efficient at the same time. Furthermore, results indicate that this mechanism applies to both, free- and forced-choice actions.