The history of marijuana use offers interesting insights into social patterns. In the 1920s and 1930s, marijuana users were mostly seamen, jazz musicians, and ghetto dwellers. By the 1960s, its use had spread to the middle and upper classes. Researchers have found that marijuana users, irrespective of their social backgrounds, seem more interested in the arts, more liberal in their political views, and less concerned with social status as compared to nonusers. On the other hand, users seem to experience difficulty communicating with others and seem less interested in organized religion.

Q. Write the signals used by the author to illustrate the spread of marijuana.