A laughing or smiling baby: this signal is almost impossible to misinterpret. When babies smile, they are happy and content. Babies don’t need a particular reason to feel happy. By smiling and laughing, your baby is telling you: “I’m doing great!”
When babies smack their lips or suck their fingers, they are often hungry. However, if they have just had a feed and do not show any other signs of hunger, they may simply be trying to settle themselves by sucking, an instinctive reflex for many babies.