The transition from implicit to explicit knowledge representations in implicit sequence learning

Implicit learning can be seen as unconscious learning process that takes place without the intention to learn and that allows to adapt to regularities in the environment. Implicit learning processes have been broadly investigated, amongst others by using the Serial Reaction Time task (SRTT; Nissen & Bullemer, 1987). With the SRTT, participants can learn a sequential structure without being informed about this structure. By means of the behavioral data as for instance reaction times one can see that the participants can learn the sequence implicitly but often do not show any explicit knowledge. The conditions and processes, under which explicit knowledge occurs in implicit learning, belong still to the contents of current research and there still does not exist any theoretical consensus among the researchers. Rather, different viewpoints about the development of explicit knowledge had been established. Furthermore, classical theories of consciousness had rarely been used to explain awareness in implicit learning (Cleeremans & Jimenéz, 2002). The goal of the current work was to investigate under which conditions explicit knowledge arises in implicit learning and to better understand the underlying processes. To answer these questions, the relevant theories had been reviewed. Furthermore, two studies had been conducted. In the review, two theoretical points of view in implicit learning, the Unexpected Event Hypothesis (UEH; Frensch et al., 2003) and the strengthening account (Cleeremans & Jimenéz, 2002), had been discussed in the context of two classical theories of consciousness, the Global Workspace Theory (GWT; Baars, 1997) and the Higher Order Thought Theories (Lau & Rosenthal, 2011). As a result, the UEH in combination with both theories of consciousness seems to be promising in explaining a multitude of findings regarding to the development of explicit knowledge in implicit learning. In Study 1, the role of unexpected events for the development of explicit knowledge was investigated. We found that the experience of an unexpected event influences the development of explicit knowledge. In contrast, implicit knowledge remains rather unaffected from unexpected events. In the second study, the behavioral components of awareness in implicit learning had been investigated. Here, the role of the strong decrease of reaction times (RT-drop; Haider & Frensch, 2005, 2009) that often accompanies the occurrence of explicit knowledge was examined. It has been shown that the RT-drop might be a behavioral consequence of rather than a precursor for the development of explicit knowledge. As soon as explicit knowledge arises, the strategy might shift from a stimulus-based to a knowledge-based task performance. If the conditions are inappropriate for a strategy shift, the old strategy may be maintained. In sum, the review and the two studies provide a good base for further research by investigating single aspects of the UEH. Both, the theoretical connection of the UEH with theories of consciousness, as well as the findings about the processes of unexpected events can help to formulate precise research questions and to systematically design future experiments