At 4-5 months, which milestone is typically achieved?

At 4-5 months, infants typically achieve the milestone of laughing. This developmental stage is characterized by significant social interaction and emotional expression. Around this age, babies demonstrate increased ability to engage with caregivers and exhibit joy through laughter in response to social stimuli, such as playful interaction or tickling.

Laughter is a key part of social development as it signals emotional connection and growing cognitive abilities. Additionally, this milestone lays the foundation for further social communication skills that will evolve as the child continues to develop.

In contrast, the other options represent milestones that occur at different ages. Walking independently generally occurs around 12 months, rolling from back to front might begin around 6 months, and speaking first words typically happens around 12 months as well. These timings reflect the typical progression of physical and language development in infants and young children.