2. Young babies have a tongue-thrust reflex. In the first four months the tongue thrust reflex protects the infant against choking. When any unusual substance is placed on the tongue, it automatically protrudes outward rather than back. Between four and six months this reflex gradually diminishes, giving the glob of cereal a fighting chance of making it from the tongue to the tummy. Not only is the mouth-end of baby's digestive tract not ready for early solids, neither is the lower end.3. Baby's swallowing mechanism is immature. Another reason not to rush solids is that the tongue and the swallowing mechanisms may not yet be ready to work together. Give a spoonful of food to an infant less than four months, and she will move it around randomly in her mouth, pushing some of it back into the pharynx where it is swallowed, some of it into the large spaces between the cheeks and gums, and some forward between the lips and out onto her chin. Between four and six months of age, most infants develop the ability to move the food from the front of the mouth to the back instead of letting it wallow around in the mouth and get spit out. Prior to four months of age, a baby's swallowing mechanism is designed to work with sucking, but not with chewing.