What is a standard infant milestone in regards to play with objects at 4 months?

At 4 months, infants typically demonstrate the ability to grasp and manipulate objects, and one of the hallmark actions is shaking a rattle or similar toy. This behavior indicates not only their developing fine motor skills but also their interest in exploring different sounds and sensations. At this stage, infants are learning about cause and effect as they discover that shaking a rattle produces noise, which can be a source of entertainment and engagement.

Grasping and shaking a rattle also signifies the coordination of hand movements and an improved grip strength, which are essential components of their motor development. This milestone aligns well with the expected abilities of a typically developing 4-month-old, who is beginning to interact more purposefully with their environment.

As infants progress beyond this age, they will develop more complex skills such as passing toys between hands or stacking blocks, but these are milestones that come later in their development. Therefore, the ability to grasp and shake a rattle at 4 months is a key standard milestone reflecting their growth in sensory and motor capabilities.