Forgetting motor programmes: retrieval dynamics in procedural memory

When motor sequences are stored in memory in a categorised manner, selective retrieval of some sequences can induce forgetting of the non-retrieved sequences. We show that such retrieval-induced forgetting (RIF) occurs not only in cued recall but also in a test assessing memory indirectly by providing novel test cues without involving recall of items. Participants learned several sequential finger movements (SFMs), each consisting of the movement of two fingers of either the left or the right hand. Subsequently, they performed retrieval practice on half of the sequences of one hand. A final task then required participants to enter letter dyads. A subset of these dyads corresponded to the previously learned sequences. RIF was present in the response times during the entering of the dyads. The finding of RIF in the slowed-down execution of motor programmes overlapping with initially trained motor sequences suggests that inhibition resolved interference between procedural representations of the acquired motor sequences of one hand during retrieval practice.