Evidence suggests there is an intrinsic difficulty in interpreting, which lies in the cognitive tasks involved. This paper presents the efforts models; a set of rather gross cognitive models of interpreting developed in the early 1980s to account for this intrinsic difficulty, and discusses their explanatory power with respect to well-known problem triggers. It then goes on to elaborate on possible implications with respect to fundamental theoretical and practical issues, to discuss methodological issues in their further exploration, and to request input from psychologists and linguists.