Before the advent of writing each of the isolated clans of the Comaquogue tribe had master storytellers whose function was to orally transmit the clan's tradition from one generation to the next. When writing was developed within certain clans of the tribe, their master storytellers disappeared within a few generations. This stands to reason, since the availability of written records obviated the need for masterful oral communicators to keep the tradition of literate clans alive. What has puzzled anthropologists, however, is the total lack of masterful storytellers in modern illiterate Comaquogue clans.

Which of the following, if true, best helps to explain the puzzling situation mentioned above?