But brain development varies.
Some children are ready earlier than others.
We researchers say that the brain needs to be able to hold a symbol in one position for reading. The child sees a straight line and a circle. Every object the child has already learned is the same object no matter what position it is in. A bottle is a bottle whether it's in the child's mouth or hand, in the refrigerator, or on the floor. A crayon is a crayon no matter what position it is in.