What developmental milestone should a 4-month-old infant be able to achieve?

At 4 months of age, an infant typically reaches certain developmental milestones that indicate their growth and progress in both motor skills and sensory development. One of the key accomplishments for a 4-month-old is the ability to hold their head erect and steady. This skill reflects the strengthening of the neck and shoulder muscles, which is essential for further physical development, such as sitting up and crawling later on.

By this age, infants have generally gained better control over their head movements, allowing them to lift their heads when lying on their stomach and to keep their heads aligned with their bodies when seated with support. This milestone is significant as it lays the groundwork for future motor skills that are crucial for exploration and interaction with their environment.

The other options represent milestones that generally occur at later ages. Rolling over typically begins around 5 to 6 months; transferring objects from hand to hand usually develops closer to 6 to 7 months; and imitating simple adult actions can be expected around 9 to 12 months.