Babies smiling at their mothers, and vice versa, were studied for signs of healthy development using a video facial tracking system.

In one finding, at around six months of age a baby will start to look away from its mother if she’s not smiling at it, which indicates interest in its environment, a normal stage of development. A failure to respond in typical ways may be indicative of developmental disorders like autism, and early detection can lead to early intervention and better outcomes.

In “Baby Smiles Provide Clues to Healthy Development,” a brief video from the National Science Foundation‘s fascinating Science Nation series, meet psychologist Daniel Messinger and some of the moms who participated in the study with their adorable smiling babies.