(NewsNation Now) — The Centers for Disease Control and Prevention updated its developmental milestones for infants and young children for the first time in nearly two decades. The change will help make it easier for parents and physicians to identify delays that could be a sign of social-communication disabilities.

The guidance was adjusted by age to account for societal changes. Experts hope the change allows parents to “learn the signs and act early” instead of waiting until the delays become more apparent.

The updates, made with the American Academy of Pediatrics, are designed to give clearer benchmarks for when children do things like acting shy around strangers, typically at six months, clapping when excited at about 15 months and engaging in pretend play near 4 years.

The agency raised the percentage of children who typically meet certain milestones from 50 percent to 75 percent, an important adjustment signifying that the majority of children are capable of certain behaviors and achievements at specified ages.

The milestone markers are based on observations, and include new indicators that a child may be autistic. The CDC also added milestones for 15 months and 30 months and clearly defined social-emotional markers such as when a child typically hugs a toy, shows affection and uses words to say, “Look at me!”

The developmental markers had not changed since they were first released in 2004.