ABSTRACT
When parents brag about their baby’s accomplishments and document their infant’s developmental achievements on calendars and smart phones, they tend to focus on physical and motor development. Parents view infants’ physical growth and motor skill acquisition as important developmental events because growing bigger and stronger and rolling over, sitting up, and so on are functionally significant, easily observable signs that children are developing normally. Psychologists, like parents, have a long tradition of using physical and motor development as a yardstick for verifying that infants are developing on schedule.
