A lot more broadly, smiling in toddlers typically appears to relate to snooze. Research implies that smiley infants who bond with mother and father at bedtime could also I generally borrow a tactic from pediatrician and writer T. Berry Brazelton, who wrote about observing infants try to capture their dad https://smileofbaby.com/how-to-get-a-fair-baby-naturally-during-pregnancy/