Movements or targets: what makes an action in action-effect learning?

According to ideomotor theory, actions become linked to the sensory feedback they contingently produce, so that anticipating the feedback automatically evokes the action it typically results from. Numerous recent studies have provided evidence in favour of such action-effect learning but left an important issue unresolved. It remains unspecified to what extent action-effect learning is based on associating effect-representations to representations of the performed movements or to representations of the targets at which the behaviour aimed at. Two experiments were designed to clarify this issue. In an acquisition phase, participants learned the contingency between key presses and effect tones. In a following test phase, key-effect and movement-effect relations were orthogonally assessed by changing the hand-key mapping for one half of the participants. Experiment 1 showed precedence for target-effect over movement-effect learning in a forced-choice RT task. In Experiment 2, target-effect learning was also shown to influence the outcome of response selection in a free-choice task. Altogether, the data indicate that both movement-effect and target-effect associations contribute to the formation of action-effect linkages-provided that movements and targets are likewise contingently related to the effects.