It may be no more than making them aware that you might give a short quiz over what they hear or that they are going to write a research paper.
Students do listen better if the instructor is present.
Past experience tells us that this type of session does not work very well. If you are going to require your students to do any type of major research whether for a project or for a paper, they would probably find a library lecture to be beneficial. We receive much positive feedback from upper division and graduate level students. Depending on the class level, we may provide overviews of the research process in the library. We cover e.