What is the primary development milestone for a 2-month-old infant?

At 2 months of age, the primary development milestone for an infant is the ability to track objects past the midline with their eyes. This skill signifies the development of visual tracking abilities and the beginning of visual and motor coordination. As infants grow, they begin to engage more with their environment, and tracking objects is one of the first signs of visual development. At this age, it is also important for infants to begin focusing on people and objects, improving their gaze and attention.

While other milestones such as rolling over, laughing, or standing with assistance are important aspects of development, they tend to occur at older ages. Rolling over usually occurs around 4 to 6 months, laughter typically emerges around 3 to 4 months, and standing with assistance usually develops even later. Hence, tracking past midline is the most appropriate milestone to identify for a 2-month-old infant, reflecting their growth in visual and cognitive capabilities.