An odd characteristic of the learning process of children is<br > known as U-shaped behavior. Very young children， even the<br > newborn， have special abilities which they spontaneously<br > seem to forget in middle childhood and have to "relearn" as<br > they grow older. This behavior is termed U-shaped after the<br > up-down-up form of the graph of the child s development.<br > Probably the most widely known U-shaped phenomenon is<br >the ability to walk. Newborn infants can walk if properly<br >supported， but this capacity disappears within a month or two<br >of birth. It does not reappear again until the infant is about a<br >year old. U-shaped behavior also is apparent in speaking.<br >When children first begin to tatk__ tko__，~ _ --~-~-~ s ~<br > ~affa past tenses correcfl~. Tloward Gardtter， a ctevelopme~xta~<br > psychologist at Harvard University， .gave the following ex-<br > ample of this (see The New York Times， September 25， 1979，<br > p. C3): Children ~vill say， for instance， "the mice came."<br > Month~ later， they~ill make mistakes， however， saying "the<br > mouses came" orf ~the mice corned." Proper usage does not<br > usually return until the age of 3 or 4.<br ><br >