In order to answer this, let us first look at what the older conceptions of race and gender were. In the time before the 1920s (and for some time after the end of that decade), most Americans believed in very traditional roles for women. They felt that the woman’s place was in the home and that women should generally act in very restrained ways. In addition to being a male-centric society, pre-1920s America was very much a white supremacist place. Most Americans believed in the superiority of the white “race” and they believed that African Americans should be deferential and unassuming. They did not want African Americans to be in any way assertive and they did not want them to be proud of their race. These were the attitudes that were challenged, at least temporarily, in the 1920s.
In the 1920s, women started to break out of the shell that had been imposed on them. This was partly because more women were working in white collar jobs and because labor-saving devices had given many women more free time. Women started to do more things in public. In particular, they started to behave in less restrained ways. They started drinking and smoking in public. They started to act in ways that were incompatible with older sexual mores. At the same time, African Americans (at least in Northern cities) became more assertive. This was a time of a tentative rise in the idea of black nationalism. The “New Negro” was proud of their race and was much less willing to defer to the supposed superiority of whites. In these ways, both women and African Americans experienced new freedoms in ways that challenged older conceptions of racial and gender relations.
The new freedoms and new types of behavior were largely centered in the cities. This led to the development of a more adversarial relationship between rural and urban America. Rural America tended to hold on to more traditional values on issues such as those of gender and religion. Because urban society was moving away from those values, the two parts of the country became more suspicious of one another. We can see this in the rise of the KKK in rural America and in things like the Scopes Monkey Trial.
The 1920s, then, were a time of great social change. The social changes challenged older ideas about race and gender (among other things) and they started to create a more adversarial relationship between cities and rural areas.
Perhaps the most iconic example of changing gender roles in the 1920s is the advent of the Flapper Girl. She is marked by her physical characteristics such as
the bob, rouge on the cheeks, powder on the knees, short skirts and ‘objectively’ cut clothing.
She is portrayed in popular literature such as the short story Bernice Bobs Her Hair which is about a young girl getting her hair bobbed for the first time. It explores the social and personal changes happening during this time.
Simply put: women started gaining freedom and they knew how to flaunt it in a non-apologetic way.