Change the activity so people have choices about what to read.
For example, in my course about the American Dream, I have everyone read Ragged Dick, among other books. All are what I would call "primary" texts. There is value to reading certain things, but I could work in choices. Perhaps in a couple of the later weeks, once people have an understanding of some of the main ideas of the course, I let them choose a book or "text" they think is about the American Dream. Then, they have to come to class prepared to talk about it, combined with a short written response on how it relates to the American Dream. This would accomplish a few things. 1. They may be more engaged because they choose. 2. They are showing they can identify the American Dream in different forms and mediums (one of the learning objectives). 3. They are also addressing writing and presenting on the humanities, another objective. Now I'm just just dispensing knowledge, but asking them to take part.