In the community, the changes presented at the ceremonies are symbolic.
These are the most significant ceremonies.
At the ceremony of one, the Newchild gets a name and is recognized for the first time as more than just a number.
For the earliest ceremony, the Naming, the Nurturers brought the newchildren to the stage. (ch 6, p. 41)
Newchildren also get a family at one. The family consists of a Father, Mother, and one child of each gender. The family units only exist for child-rearing purposes, and the couple has to apply for a child and be approved by the committee.
Jonas describes the ceremonies of Two, Three and Four as boring. Children are not really considered significant until Three. “Dream-telling began with Threes” (ch 5, p. 35) and language instruction is important at this age.
The ceremonies of Four, Five, and Six are basically just the children aging one more year.
Fours, Fives, and Sixes all wore jackets that fastened down the back so that they would have to help each other dress and would learn interdependence. (ch 6, p. 40)
At Seven, children get front-button jackets. This is significant because until that point the jackets have buttoned in the back. This change is “the first sign of independence” (ch 6, p. 41).
At Eight, children begin volunteer hours, and yet another sign of growing independence.
Lily… became an Eight and received the identifying jacket that she would wear this year, this one with smaller buttons and, for the first time, pockets, indicating that she was mature enough now to keep track of her own small belongings. (ch 6, p. 45)
At Nine, children receive one of the most coveted gifts: the bicycle. They have been secretly taught how to ride them. The bicycle is a strong symbol of moving away from the family unit, out into the community.
Tens get a haircut, so the ceremony is a bit more time consuming.
[Each] child's hair was snipped neatly into its distinguishing cut: females lost their braids at Ten, and males, too, relinquished their long childish hair and took on the more manly short style which exposed their ears. (p. 46)
Elevens are pretty much just waiting to be Twelve. The females get bras and the children get clothes with special pockets for a new calculator.
Twelve is the most significant ceremony in some ways, because it is the last one. At Twelve children are no longer really children. They are young adults. They no longer are designated by age, but rather by occupation. Their occupations are chosen for them by a committee of Elders.
Lowry, Lois (1993-04-26). The Giver (Newbery Medal Book). Houghton Mifflin Harcourt. Kindle Edition.