From the very first week active infants reach for interesting objects that are within their reach.
By 4 months infants are becoming quite good at bringing their hands to a toy and sometimes they succeed at grabbing it as well. Th difficult part of grasping is shaping and positioning the hand for easy grasp.
Infants require lots of practice to get this right. The trick is to position the infant's favorite toys so that they can be reached, touched, felt and grasped and importantly the toy should stay in place so that the infant can go back to it many times.
When an infant lies in a soft bouncy chair he is supported at an angle and the toys can be fastened to the cross bar or put on his lap.
Will (16 weeks) playing with a favorite flower
This clip shows Will reaching for a cloth flower sometimes with one hand and sometimes with both hands. The petal of the flower are soft and easy to grasp. Watch how he pays attention to his hands when fingering the flower. He is working hard at figuring how to position his hand and fingers so that he can grasp the petals.
Will playing with a toy crab
The toy crab also has interesting bits that can be easily grabbed. It rests on his lap and the side of the bouncy chair stops it from falling off.
Also watch how Will practices moving his hands wide apart and then bringing them together again. Sometimes they meet in the midline, and at other times they pass each other. He is busy getting the hang of controlling the the movement of the arms to bring the hands to the same place at the same time.