Evidence for parallel explicit and implicit sequence learning systems in older adults.

Some research indicates that explicit learning of a sequence can impair procedural learning, particularly in populations with reduced cognitive capacity. However, these studies usually do not distinguish the effects of explicit processes on procedural learning from their effects on performance. The current study demonstrates that explicit learning affects performance, but not procedural sequence learning, in healthy older adults even when sequences are complex. These findings support capacity-independent theories which propose that procedural and declarative learning operate in parallel.