Although television debuted during the late 1920s, it did not become popular in the United States until after World War II. Early television programming consisted of television shows that were extensions of radio programs, often using the same variety-style format and entertainers. For instance, Milton Berle transitioned from radio to television in the late 1940s.
During the mid-1950s other types of programs---situation comedies (sit-coms), live dramas, Westerns and children's shows---added variety to the programming of the three American networks (ABC, CBS and NBC). In the early 1960s, James Aubrey became president of the CBS network where he pioneered what has been called "the least objectionable program theory," meaning that he put programs on CBS that appealed to a wide range of viewers. CBS's success inspired the other two networks to adopt similar programming policies.
In the 1970s, Home Box Office (HBO) began offering movies by subscription to cable stations. Other cable networks followed, resulting in niche programming with entire networks dedicated to a particular demographic by the 1980s.
Although sporadic examples of reality TV shows like Candid Camera existed prior to the 1990s, the modern era of reality television began with Music Television's (MTV) The Real World in 1992. Because reality TV shows are cheaper to produce than scripted programs, reality programming has become more popular as the explosion of networks has made advertising dollars more scarce.
The history of TV programming reflects the cultural and social changes that the United States has undergone since the debut of television. The changing position of women in society, the end of legal segregation and the growing acceptance of gays and lesbians are issues that have changed the types of programs networks air.