9 Months: Stranger Anxiety and Sitting Solo

Around 9 months, many babies show clearer stranger anxiety and can sit without support.

Social/Emotional

Often shy, clingy, or fearful around strangers.
Shows several expressions, like happy, sad, angry, surprised.
Looks when you call their name.
Notices a caregiver leaving the room.
Enjoys interactive games like peek-a-boo.

Language/Communication

Makes repetitive sounds such as “mamamama” and “bababababa.”
May raise arms to signal wanting to be picked up.

Cognitive (Learning, Thinking, Problem-Solving)

Looks for objects when dropped out of sight, like a spoon or toy.
Bangs two things together.

Movement/Physical Development

Sits without support.
Moves objects from one hand to the other.
Uses a raking motion to pick up food.

Caregiving Tip

Stranger anxiety is considered a sign a baby can tell familiar caregivers apart from strangers, and a normal part of development. Giving your baby time to adjust to someone new, rather than picking them up suddenly, can help.

When to Consider Talking with a Pediatrician

If your baby still can’t sit without support, shows no babbling, or doesn’t respond to their name, discuss it with a pediatric provider. This information isn’t a diagnostic tool and doesn’t replace advice from a medical professional.

Sources

CDC (Centers for Disease Control and Prevention) - Learn the Signs. Act Early.