Smile Back at Your Baby — It's Shaping Their Emotional Development

Here's something beautiful to carry into your next play session: when you and your baby smile at each other at the same time, you're doing more than sharing a sweet moment — you may be helping your baby learn to regulate their emotions.

Two new studies, reported this month, followed nearly 1,000 four-month-olds and tracked their heart-rate patterns during play with their mothers. Researchers looked at a measure called respiratory sinus arrhythmia — a pattern of heart-rate variability tied to emotional regulation. The striking finding: those regulation-linked patterns only appeared when baby and caregiver were smiling at each other simultaneously. When only the baby smiled, or only the mother smiled, the pattern didn't show up.

"Play is not just fun and games. It's influencing the baby's physiology," said Daniel Messinger, the University of Miami psychology professor who led the research.

So the next time those gummy grins come out — smile back, be silly, make the faces. Every shared smile counts.