Every baby grows at their own pace; these milestones show common patterns, not strict deadlines.

Month 3–4: Growing Awareness & Early Control

Social & Emotional

• Smiles often and responds to your smiles
• Enjoys face-to-face play
• Gets excited when you walk into the room
• May copy your facial expressions

Communication

• Makes louder coos, gurgles, and squeals
• Uses sound + movement together (kicks while “talking”)
• Turns toward your voice consistently
• Begins early “back-and-forth” conversations

Movement / Motor

• Holds head steady without support
• Pushes up on forearms during tummy time
• May start rolling tummy to back
• Brings hands to mouth
• Reaches for toys, though not always accurately

Thinking / Cognitive

• Follows moving objects smoothly side to side
• Looks around the room with curiosity
• Shows interest in textures and new sounds
• Anticipates feeding or cuddling routines

Month 4–5: Stronger Body, Clearer Communication

Social & Emotional

• Laughs out loud
• Shows more personality
• Enjoys playful interactions (peek-a-boo beginnings!)
• May show preference for familiar people

Communication

• Makes more varied sounds (“ah-goo,” squeals, giggles)
• Experiments with volume
• May begin babbling consonant-like noises
• Recognizes caregivers’ voices and faces quickly

Movement / Motor

• Rolls from stomach to back and may begin back-to-stomach
• Holds toys when placed in hand
• Reaches with more accuracy
• Pushes up on hands, not just forearms
• Sits with support (pillows, your hands, or a seat)

Thinking / Cognitive

• Explores toys by shaking, banging, or mouthing
• Tracks objects across longer distances
• Understands cause and effect (drops toy → looks to see what happens)
• Shows curiosity about mirrors and faces

Month 4–5: Stronger Body, Clearer Communication

Social & Emotional

• Laughs out loud
• Shows more personality
• Enjoys playful interactions (peek-a-boo beginnings!)
• May show preference for familiar people

Communication

• Makes more varied sounds (“ah-goo,” squeals, giggles)
• Experiments with volume
• May begin babbling consonant-like noises
• Recognizes caregivers’ voices and faces quickly

Movement / Motor

• Rolls from stomach to back and may begin back-to-stomach
• Holds toys when placed in hand
• Reaches with more accuracy
• Pushes up on hands, not just forearms
• Sits with support (pillows, your hands, or a seat)

Thinking / Cognitive

• Explores toys by shaking, banging, or mouthing
• Tracks objects across longer distances
• Understands cause and effect (drops toy → looks to see what happens)
• Shows curiosity about mirrors and faces

Month 5–6: Emerging Skills & Early Independence

Social & Emotional

• Smiles and laughs during games
• Responds to emotion in your voice
• Shows excitement with full-body wiggles
• May show early signs of shyness with strangers

Communication

• Babbling begins (“ba,” “da,” “ma”-like sounds)
• Uses sounds to get attention
• Responds to their name (or at least turns to the sound)
• Expresses joy and frustration with clear sounds and faces

Movement / Motor

• Rolls both directions
• Sits with minimal support; some babies may sit briefly without help
• Pushes up high in tummy time (almost a mini push-up)
• Bears weight on legs when held standing
• Reaches, grabs, and transfers objects between hands
• Beginning to pivot or scoot in tummy time

Thinking / Cognitive

• Looks for a dropped toy
• Shows interest in cause-and-effect toys (rattles, crinkle books)
• Explores objects with hands and mouth
• Recognizes familiar routines and may get excited before feeding, bath, or play
• Starting early object permanence (may look for you when you walk away)

From 3–6 months, babies become more social, more coordinated, and more curious.
They begin rolling, laughing, babbling, and exploring their world with hands, eyes, and mouth.

You can support their growth with:

• Tummy time
• Talking and singing
• Face-to-face play
• Letting them safely explore objects

Citations: 

Centers for Disease Control and Prevention. (2024). Important milestones: Your baby at four months. U.S. Department of Health & Human Services.

Centers for Disease Control and Prevention. (2024). Important milestones: Your baby at six months. U.S. Department of Health & Human Services.

American Academy of Pediatrics. (2023). Developmental milestones: Baby 3–6 months. 

American Academy of Pediatrics. (2023). Baby’s first year: Developmental stages.

World Health Organization. (2023). Infant development and early childhood growth standards.

Zerotothree. (2023). Baby development: 3–6 month milestones.

Johnson, S., & Marlow, N. (2011). Early developmental milestones and later development. Archives of Disease in Childhood, 96(7), 641–648.