Sleep and awareness about presence of regularity speed the transition from implicit to explicit knowledge

Sleep supports the conversion of implicitly acquired information into explicitly available knowledge. Currently, it is unclear if awareness about the presence of regularities in the stimulus material can modulate this conversion. Forty participants were trained on a serial reaction time task (SRTF). Twenty participants were informed afterwards that there was some regularity in the underlying sequence, without giving them any specific details about this regularity (aware condition); twenty other participants were not informed (unaware condition). Ten participants in each group slept the night after training, whereas 10 remained awake. After a second night of (recovery) sleep, a generation task followed where the target positions of the trained SRTT had to be deliberately generated. Both sleep and awareness improved generation task performance, but the two factors did not interact. We conclude that whilst sleep facilitates the conversion of implicit into explicit knowledge, the effect of awareness is not specific to sleep-dependent consolidation. (C) 2010 Elsevier B.V. All rights reserved.