Implicit and explicit learning in young adults with mental retardation.

We examined intelligence-related differences in explicit and implicit learning using an artificial grammar paradigm. Young adults with and without mental retardation completed a sequence-learning and identification task. For some participants, sequences were constructed following an artificial grammar; for others, sequences were random. Explicit learning was determined by ability to learn and later identify random sequences. Implicit learning was determined by the tendency to incorrectly identify new grammatical sequences as seen before, relative to new nongrammatical sequences. Participants with mental retardation did more poorly than participants without mental retardation on explicit learning but just as well on implicit learning. Results suggest that learning of complex materials, when accomplished through implicit processing, is functionally equivalent in individuals with and without mental retardation.