The foundation for social communication is present from birth, with newborns preferring to orient to faces over non-faces and caregivers over strangers. Between 9-12 months of age, infants develop other social communication skills such as use of eye gaze, facial expressions, gestures, and sounds. Differences in social communication are a defining feature of autism spectrum disorder (ASD). There’s minimal prior research that examines whether observable prelinguistic social-communication skills, prior to 12 months of age, emerge more slowly in infants with ASD compared to typically developing infants. A new study documents that observable social-communication differences for infants with ASD unfold by 9 months, pointing to a critical window for targeted intervention.