Repetition effects reveal the subsequence representation of actions

Many motor skills involve combining movements into sequences. After a single execution, humans retain a memory trace that speeds up repeated sequences. Consistent with previous work, our results show a repetition benefit even when only a small subsequence is repeated, suggesting that full sequence repetition is not necessary. This memory trace is activated when the last 2–3 movements match the current execution. Our work, therefore, sheds light on the structure of the earliest sequence memory.