Sleep Promotes the Extraction of Grammatical Rules
Exposure to the grammar took place during a short-term memory task. Each sequence was centrally presented letter-by-letter on a computer screen (2.7–6.9 s corresponding to 5–12 letters; 300 ms letter presentation, * = 300 ms inter-letter interval). Participants were randomly assigned to one of five groups with offline delays of varying length (15 min, 12 h, and 24 h). The delay of two groups contained nocturnal sleep (black lines, 12 h e-m and 24 h e-e). During the test phase, participants judged if novel sequences were Grammatical (G), or Non-Grammatical (NG). The letters were presented one by one, similarly to the short-term memory cover task. m = morning, e = evening.