Multimedia information retrieval systems design is currently considered a complex task since it requires an understanding of users specific way of searching, processing and using data conveyed by different media (texts, images, videos, sounds etc.). In this work we first discuss the state of the art of research in the field of textual and visual information retrieval approaching its problems from a user-centred perspective. We then propose a general framework derived from recent studies in social and cognitive ergonomics that should prove useful to guide the design and evaluation of user-system interaction in a multimedia context. We also provide some examples of social and cognitive factors affecting both the design and the evaluation of multimedia systems interfaces, discussing them with particular reference to the field of Digital Libraries. We conclude by stressing some points of strength of our approach and by suggesting new research issues to be further investigated.