Are afternoon naps key to enhancing learning?

Maybe cats and kindergartners are on to something: Recent research out of the University of California, Berkeley suggests that taking an afternoon nap might lead to increases in learning ability throughout the day! Research out of the the Sleep & Memory Lab led by Matt Walker up at UCB shows that, in general, our learning abilities decrease over the course of a day. So, when people are asked to memorize a list of words at noon, and then to memorize a different list of words at 6 PM, they perform much worse when attempting to learn the words in the evening compared to midday. However, if people were given the opportunity to take a 90 min. nap in between the sessions, they actually learned MORE at 6 PM compared to at 12 noon! Results like these suggest that sleep is important not just for memory, but also for learning abilities. Of course much more research is needed to determine how long of a nap is ideal (what if you only have 30 min. instead of 90 min. to nap in the middle of the day? will you still learn better? is there such thing as too long of a nap?) and the exact conditions under which naps are beneficial, but maybe a little mid-day shut eye would be beneficial to all of us!