Many babies begin their "sucking" journey in the womb. Sucking is a natural reflex that babies have from birth that is essential for their survival. It is part of the suck, swallowing, and breathing mechanisms developed in infancy during feeding and is responsible for the maintenance and development of many human functions and behaviors.
This includes posture and motor development, visual motor skills and development, language and speech development, and emotional/social development. You can also help your child to stop sucking finger via https://www.amazon.co.uk/Age-2-7-Stop-Thumb-Sucking/dp/B00VQU2DZS.
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Many babies like a mannequin or thumb to calm themselves down when they are upset or tired. There are a nerve and blood supply just behind the upper front teeth. This particular area is stimulated by sucking on the thumb, finger, or mannequin. Studies show that in these cases when hormones such as serotonin and dopamine are released, nerve transmission in the brain decreases. These hormones create feelings of calm, comfort, and relaxation.
As they get older, many children continue to suckle their fingers and thumbs, toys, blankets, pens and pencils, hair, and clothes to stay alert, focused, and stay calm, and in control.
If by the age of four the child doesn't stop, then this has become a habit. And regardless of negative reviews from mom, dad, aunt, or the perfect stranger on the street; Often there are mood-boosting hormonal rewards for children that go beyond the most disapproving reactions. In many children, prolonged sucking may be the result of an underdeveloped absorption mechanism.
If you have a child who sucks a thumb or finger, early intervention is the best way for children to have the best chance of having a beautiful face and a natural, healthy smile.