Of particular interest to folklorists here is the mode of transmission of these artifacts; this lore circulates exclusively within an informal pre-literate children's network or folk group. It does not include artifacts taught to children by adults. However children can take the taught and teach it further to other children, turning it into childlore. Or they can take the artifacts and turn them into something else; so Old McDonald's farm is transformed from animal noises to the scatological version of animal poop. This childlore is characterized by "its lack of dependence on literary and fixed form. Children…operate among themselves in a world of informal and oral communication, unimpeded by the necessity of maintaining and transmitting information by written means. This is as close as folklorists can come to observing the transmission and social function of this folk knowledge before the spread of literacy during the 19th century.