A dumb Dora is considered to be 1920s

1920s

File:1920s decade montage.png|From left, clockwise: Third Tipperary Brigade Flying Column No. 2 under Sean Hogan during the Irish Civil War; Prohibition agents destroying barrels of alcohol in accordance to the 18th amendment, which made alcoholic beverages illegal throughout the entire decade; In...

 American slang

American slang

American slang is slang that is common in, or particular to, the United States.The term can refer specifically to:-Language:*California slang, slang used in California English, or which originates in California*U.S...

 for a completely idiotic woman

Woman

A woman , pl: women is a female human. The term woman is usually reserved for an adult, with the term girl being the usual term for a female child or adolescent...

.

The phrase was made popular from the vaudeville

Vaudeville

Vaudeville was a theatrical genre of variety entertainment in the United States and Canada from the early 1880s until the early 1930s. Each performance was made up of a series of separate, unrelated acts grouped together on a common bill...

 acts of George Burns

George Burns

George Burns , born Nathan Birnbaum, was an American comedian, actor, and writer.He was one of the few entertainers whose career successfully spanned vaudeville, film, radio, television and movies, with and without his wife, Gracie Allen. His arched eyebrow and cigar smoke punctuation became...

 and Gracie Allen

Gracie Allen

Grace Ethel Cecile Rosalie Allen , known as Gracie Allen, was an American comedian who became internationally famous as the zany partner and comic foil of husband George Burns...

 (who played the actual role of Dumb Dora); eventually becoming a name of a classic comic strip by King Features Syndicate

King Features Syndicate

King Features Syndicate, a print syndication company owned by The Hearst Corporation, distributes about 150 comic strips, newspaper columns, editorial cartoons, puzzles and games to nearly 5000 newspapers worldwide...

. The comic strip was discontinued in 1935 despite the high was given a new lease on life in the 1970s on a CBS

CBS

CBS Broadcasting Inc. is a major US commercial broadcasting television network, which started as a radio network. The name is derived from the initials of the network's former name, Columbia Broadcasting System. The network is sometimes referred to as the "Eye Network" in reference to the shape of...

 game show called Match Game

Match Game

Match Game is an American television game show in which contestants attempted to match celebrities' answers to fill-in-the-blank questions...

; extending the routine to audience

Audience

An audience is a group of people who participate in a show or encounter a work of art, literature , theatre, music or academics in any medium...

 participation. Members who were watching in the studio would shout the phrase How dumb is she? in total unison. Flapper

Flapper

Flapper in the 1920s was a term applied to a "new breed" of young Western women who wore short skirts, bobbed their hair, listened to jazz, and flaunted their disdain for what was then considered acceptable behavior...

s during the 1920s shared many of the same common charateristics of a dumb Dora.