From birth infants are visually curious and want to see what is going on. Their attention is easily captured by brightly colored moving objects. They also show an early preference for faces and hands, those of other people as well as their own.
This visual curiosity is important stimulus for learning to control the position of the head. Having a steady head makes it a lot easier yo see clearly.
Here you see how Toesies at 13 weeks (8 weeks corrected age) carefully watches my hands as I move them above his head.
Use your hands to encourage your infant to maintain visual attention for a short period of time, to look in different directions, turn the head or steady the head in the midline.
In this video you see Toesies watching my hands. Notice how his leg and arm movements quieten as his attention is focused on my hands.
Later on in the video I move my hands close to my face to get him to look at me so that we can have a chat.