By far the biggest contribution that the Younger family make towards the progression of society is buying a house in a white area and putting up with the conflict that this produces both in their black community, as depicted in the character of Mrs. Johnson, the Younger's neighbour, but also in the white community, as depicted in the character of Mr. Lindner, who offers the Younger family money to not move into their new home. Note what Mrs. Johnson says to Mama and Ruth about the "pride" of the Younger family in wanting to improve their social position:
The Youngers is too much for me! You sure one proud-acting bunch of coloured folks. Well--I always thinks like Booker T. Washington said that time--"Educatino has spoiled many a good plow hand"--
It is the stubborn insistence and pursuit of a better life by the Younger family that is their chief contribution to progression. The Youngers determine to move into a white area. Beneatha still sets her sights on studying to become a doctor, which was a radical thing for a woman to do back then, let alone a black woman. Walter believes that he is meant for more than working for another man. Each of these characters, and the Younger family as a whole, have to combat significant barriers in order to pursue their dreams, but in pursuing them they are fighting an important battle for social change.