"In both of our experiments, only those infants who took an extended nap for at least half an hour within four hours after learning remembered the information."
– It's long been thought that napping is an important part of a baby's growth—both physically and mentally. Now new research in the Proceedings of the National Academy of Sciences suggests that naps help babies form new memories, and that when a nap directly follows a new activity the baby is far likelier to recall it the next day than if that child doesn't nap until four hours after the activity, reports the Los Angeles Times. "In both of our experiments, only those infants who took an extended nap for at least half an hour within four hours after learning remembered the information," the study's lead author tells HealthDay News. To test a baby's recall, researchers studied 216 babies ages 6 months and 12 months. They demonstrated how to remove mittens from animal puppets, and found that those who then took naps at least 30 minutes long (and typically more like 80) were better able to recall how to remove the mittens 24 hours later than those who didn't nap until four hours later. Whether a baby napped just before the experiment made no difference. The authors also hypothesize that because the hippocampal region—key to memory formation—is so small in babies, it may only be able to store smaller chunks of information, hence the need for frequent sleep early in life. (Other research shows a newborn's brain grows 1% a day.)