When babies are tired, they often show it by rubbing their face, tugging on their ... along with quick breathing and a pained expression, could be a sign that baby is either a bit frustrated ...

Baby monkeys who receive more care from their mothers develop stronger facial expression recognition skills as they grow ... They spent significantly more time looking at the final, different face, ...

so they can see your face and follow your expressions. If you get up close to your baby as you're talking to them, they can watch the movements you make with your face as you speak and they listen ...