Learning and Generalizing Non-Adjacency in 18 Month-Olds: The Role of Naps

Abstract

Research investigating the role of sleep in infant language learning has yielded several important results regarding rule learning. Fifteen month-old infants demonstrated how naps between exposure to a language and test encouraged the abstraction of a non-adjacent dependency rule governing the strings of the language (Gomez et al. 2006). Further, sleep within a short interval of exposure helped infants maintain this rule in memory 24 hours later (Hupbach, A., Gomez, R., Bootzin, R. & Nadel, L, 2009). However, it is unclear how these rules are applied to novel stimuli. In the present study, 18 month-old infants were presented with an artificial language guided by a rule of non-adjacency, where the first word of a string always predicts the final third word. Four hours later, after either napping or remaining awake, infants were tested on applying this rule to new vocabulary. We demonstrate that a nap during the interval between exposure and test not only facilitates rule abstraction, but also generalization to novel vocabulary following the same rule. Infants who did not nap between exposure and test did not show the same learning compared with napping infants. Naps seem to promote rule abstraction.