Roots of smile: A preterm neonates' study.
Kiyobumi Kawakami, Kiyoko Takai-Kawakami, Fumito Kawakami, Masaki Tomonaga, Makoto Suzuki, Yukiko ShimizuDOI: 10.1016/j.infbeh.2008.03.002
Twenty-two preterm neonates were observed 1 h per neonate in the NICU. Ninety-five spontaneous smiles were recorded. Younger and smaller neonates showed more and longer spontaneous smiles than older and larger. The youngest neonate was 200 days from conception on the observational day. She was 511 g. This infant showed spontaneous smiles. The roots of spontaneous smiles are discussed.