The child will lie prone on the large ball, you hold the child and the large ball slowly rocking back and forth, you can also help the child sit on the large ball upside down, the child is very fond of this activity, this is because the development of balance in the brain needs the sensory stimulation of movement. Children like the feeling of movement from birth. Hold the baby gently shake, up and down, or hold in the house to walk back and forth, will make the baby comfortable and happy. By 5 months, some infants like to be held and bounced, but also like to rotate, back and forth, and swing from side to side. The reason infants are so interested in these activities is that they are born with a very well-developed vestibular system, a sense of balance that allows humans to master body movement and balance. The vestibular sense is the first sensory organ to develop during fetal life, along with the sense of touch. It is a special device in the inner ear that senses changes in your body position and adjusts your limbs to maintain balance. Intellectual development is a cumulative process, and the vestibular system is one of the first senses to develop, accounting for a large part of an infant’s early sensory experience. These experiences may have a critical role in integrating other senses and movement, and so also influence higher-level emotional development and cognitive abilities. Research now demonstrates that increased motor stimulation of the vestibule can lead to earlier development of sitting, crawling, standing, and walking movements.