Neuroscientist William Fishbein says that deep, "slow-wave" sleep can help us commit information to memory, learn new skills, and extrapolate information. Science news site Physorg reports that Fishbein and a graduate student studied English-speaking students' ability to remember Chinese characters they were taught just before a nap (and some without a nap):
Upon awakening, they took a multiple-choice test of Chinese words they'd never seen before. The nappers did much better at automatically learning that the first of the two-pair characters in the words they'd memorized earlier always meant the same thing—female, for example. So they also were more likely than non-nappers to choose that a new word containing that character meant "princess" and not "ape."