with some studies demonstrating consolidation while others did not.
The emphasis on either the explicit or implicit component of sequence learning in these studies may have contributed to the seemingly contradictory findings.
Ghilardi and colleagues (2009) demonstrated a dissociation in consolidation between the explicit and implicit components, using a task that combined both.
Explicit recall of the initial sequence (sequence A) was interfered with to the same degree regardless of whether a second sequence (sequence B)was learned 5 minutes or 24 hours after sequence B. Implicit learning of sequence A, however, showed a window of susceptibility to interference by sequence B, which was evident when the interval between sequence A and B was 5 minutes but not at 24 hours. Both components of sequence learning showed resistance to interference with more prolonged training of the initial sequence. A similar beneficial effect of prolonged training on retention and consolidation has been suggested by studies of motor adaptation, and explicit learning.
The benefit of prolonged performance at asymptote may relate to the observation that repeated testing itself enhances retention, as demonstrated by Karpicke and Roediger (2008) using an explicitlearning task.