How implicit is implicit learning?

Abstract This chapter discusses the early demonstrations of implicit learning, which includes artificial grammar learning, sequence learning, control of complex systems, and the acquisition of invariant characteristics. Subsequent changes and the distinct properties of storage and retrieval of implicitly acquired knowledge are also discussed in this chapter. This chapter states that the term ‘implicit learning’ has been used to characterize situations were we learn to recognize and produce grammatical utterances without ever being able to describe the underlying rules of the grammar and reviews and assesses the evidence in relation to the two main features of implicit learning that was proposed by Reber (1989). The first feature states that implicit learning gives rise to abstract knowledge; while the second states that it is an unconscious process. It is suggested that with the problem of assessing implicitly acquired knowledge and interpreting the results of the different knowledge measures, seeing whether such knowledge can be distinguished on other grounds will be a profitable approach. It also analyzes whether implicitly acquired knowledge is associated with properties of storage and retrieval. It is concluded that learning may be considered to be implicit in some senses, but not in others.