In this paper we present a way to increase the efficiency of the learning process, dividing the student population into several different categories depending on what we call "Natural-Learning-Style ". To define this kind of style, we need a background of philosophical and psychological theory allowing us to contain the aims of the COLOS project, the main of which is the intuitive learning and natural representation of physics. We describe a method to decide a student's main type of category. In another step we explain in which way the human interface of a CAT/CAL product must be designed with respect to the considered type, that means to define a "Learning Environment ". We present some principles enabling software to adapt its own interface to the user, then we discuss how to build CAT/CAL packages applying these ideas. 2. Background The COLOS project -- where COLOS stands for "COnceptional Learning Of Science" -- consists of ten groups from universities of seven European countries...