After learning words, do babies who nap remember them and apply them to new objects of the same kind?

Details

The researchers examined whether sleep helps babies move beyond remembering a word for a particular object to applying it to other objects in the same category. Infants were given opportunities to learn both kinds of word meaning. Their initial brain electrical responses indicated learning of the particular word–object links, but not the broader category meanings.

About 1.5 hours later, only the infants who had napped showed evidence of both remembering the original links and extending the words to new examples of the category. This suggests that a nap may support not just remembering recently learned words, but also using them more broadly. The evidence came from brain responses rather than spoken answers.

The broader application of words was also correlated with sleep spindle activity during the nap, independently of age. This suggests a possible role for sleep spindles in learning, but the correlation does not establish that they caused the effect. The abstract does not report sample size or random assignment, limiting assessment of how firmly the nap itself explains the group difference.