Because of massive social change and mechanical and electronic reproduction of images and text, the contemporary audience is familiar with images of the past as part of everyday life. This exposure to mass images does not, of course, make them an audience of consumers in the artworld. The more popular the artwork the more cultural meaning is brought to it by the audience. There are many cultural contexts that audiences belong to or are part of. Audiences respond in different ways.
Audiences expect change.
Artworks can have multiple audiences. A curator may construct an exhibition to represent a point of view to an audience. But the viewers coming to that exhibition have many different backgrounds and experiences and may form different interpretations. Some responses by audiences are shared but others will be individual responses. You need to understand how this changes over time and how different audiences have their own experiences which are culture-bound and therefore bring different meanings to their responses.