What does the professor mean by the term "cultural narrator"?

Throughout most of human history, a society’s culture was defined and communicated primarily through the family. Early cultures communicated their values and beliefs to their children by oral tradition-word of mouth. Parents and grandparents had the job of passing on the culture’s history and traditions. The older members of the family were storytellers and historians-our "cultural narrators."
The cultural narrator was valued for his or her wisdom and experience. The cultural narrator helped to sustain the society through the preservation of vital cultural information. Until the mid-twentieth century, the family was the medium by which culture was passed along.
Since the 1950s, however, the role of the cultural narrator has been taken over by television. What I mean is, the family storytellers have been replaced by television shows that tell us who we are, what we need, how we should speak, and what we should believe in.
In the sixties and seventies, as television became more a part of North American life, several writers and philosophers began to study what was going on. One of the most creative minds to explore this issue was Marshall McLuhan.
McLuhan studied English literature in his native Canada and in England, and then taught at several universities in the United States. As a Canadian scholar teaching in the U. S., McLuhan realized that he didn’t understand his American students. He couldn’t figure out their interests and values, why they spoke and acted and felt the way they did. So, he set out to learn more about the values of his students by studying their popular culture: the movies, television shows, music, pastimes-all the things that young Americans pursued in their leisure time.
McLuhan became convinced that electronic media played a significant role and that the media were responsible for the attitudes and values of his students. In fact, he went beyond his immediate interest in his own students to theorize that the media had prompted most of the social changes in Western culture. McLuhan’s ideas soon made him the leading cultural critic and media theorist of his time.
McLuhan’s ideas gained attention worldwide. He wrote several books about the effect of media on human development, including this one, The Medium is the Message, which is the book you’ll be reading next in this course.
The Medium is the Message is McLuhan’s most influential book. Although it was first published more than thirty years ago, it remains an important classic in the field of communications. It’s a book-and an idea-that you’ll come back to over and over again, and reading it will probably change your view of how we communicate.
Why is it such an important book? Well, you’ve probably heard the expression, "The medium is the message" because it’s entered our vocabulary. What McLuhan meant by this statement was that how people learn-the medium-is more important than what they learn-the message. In other words. the method of communicating information has more influence on the public than the information itself. Communication is culture, and-culture is communication.
McLuhan didn’t consider himself a critic of the media in the sense of condemning it. He wasn’t interested in deciding whether television was good or bad. He just wanted people to understand how it affected them so they could make their own informed decisions about it. We’re just beginning to understand the ways that the media have affected our culture. Sociologists, psychologists, media ecologists-people in a multitude of fields are trying to explain the relationships among media, values, and behavior.
Is television good or bad for us? Does television cause human behavior, or merely record it? This question is of particular interest to researchers who study the effects of television-especially television violence-on children’s behavior. And now that television is starting to merge with other electronic media, like the Internet, there are a growing number of issues and new questions calling for informed thinking about the relationship of the media to human development.