Scientists say they have cracked the mystery of your baby’s smile.

Think it’s your sparkling wit? Researchers at the University of California have released a new study in PLOS ONE that suggests babies who smile are attempting to make the person they’re interacting with smile back. “By the time infants reach 4 months of age both mothers and infants time their smiles in a purposeful, goal-oriented manner. In our study, mothers consistently attempted to maximize the time spent in mutual smiling, while infants tried to maximize mother-only smile time,” a researcher tells the San Diego Union-Tribune. Scientists reverse engineered face-to-face interactions of 13 mothers and babies with their babies, aged 4 to 17 weeks and determined that the babies tried to maximize their mother’s smiling while minimizing their own, timing out their smiles (which require effort) to ensure the mother continues to smile, even as they take occasional breaks. Hey, being a baby is a hard work. (Fox) (Image: flickr.com)