Testing enhances motor practice.

We investigated how retrieval of a set of newly learned motor sequences influences subsequent learning of another set of motor sequences. In four experiments, retrieval reduced an acceleration of movement execution over subsequent study trials. This relative slowing-down was associated with better recall performance in a final memory test. Explicit retrievability of motor sequences benefited from longer study-trial response times (RTs), suggesting that retrieval caused more attentive encoding. The use of motor sequences requiring overt action during encoding allowed for this demonstration of a twofold forward effect of testing on encoding quality and on recall. Experiment 1 adopted a paradigm used in previous studies with verbal materials. Experiment 2 changed the test format to be less susceptible to interference. Experiments 3 and 4 additionally switched from a between-participants design to a within-participants design. These modifications did not affect the occurrence of the twofold forward effect of testing but enabled detecting a correlation between recall and study-trial performance that had been precluded by the strongly interference-dependent test format of the original paradigm. Our findings demonstrate an immediate learning benefit of testing. It enhances encoding in subsequent study trials.