Abstract
Adaptive aiding is a human-machine system design concept that involves using aiding/automation only at those points in time when human performance in a system needs support to meet operational requirements---in the absence of such needs, human performance remains unaided/manual, and thereby humans remain very much "in the loop." This paper describes the evolution and results of an ongoing program of experimental and theoretical research in adaptive aiding. The development and proof of concept are first discussed, followed by consideration of human performance models, on-line assessment methods, and the psychology of human-aid interaction. The implications of these ideas and results are discussed relative to design of intelligent support systems in general and expert systems in particular. A framework for design is presented that includes a structured set of design questions that may be addressed in terms of principles of adaptation and principles of interaction.