Description

The main aim of the project was to investigate relations between sleep and memory processing in the first year of life. In a series of four studies, we consistently found evidence of sleep and memory being closely intertwined early in life, extending previous findings obtained with adult populations. In all studies, we used an imitation procedure where a model demonstrated actions to infants using a hand puppet and the infants’ ability to reproduce these actions was assessed immediately (Study 2) or after delays of 4- (Study 1, Exp. 1; Studies 3 and 4) or 24-hrs (Study 1, Exp. 2). In Studies 1, 3 and 4, an experimental approach was used where infants were randomly assigned to nap, no-nap, and baseline control conditions, providing the opportunity to explore cause-effect relations. In Study 2, a correlational approach was used, supplementing the experimental data. In Study 1 we found that post-learning naps facilitated 6- and 12-month-old infants’ declarative memory consolidation. Study 2 revealed that high quality night sleep was associated with enhanced rates of immediate imitation the following day in 6- but not 12-month-olds. In Study 3 we found that post-learning naps facilitated 12-month-old infants’ ability to apply previously learned information to a novel stimulus. Study 4 showed that post-learning naps enhanced 12-month-old infants’ ability to extract the gist from a learning episode. Together, the studies suggest that sleeping behaviour is an important influence on early human memory.