Formal educational environments often provide less support for learning than do the everyday environments available to young children. This paper considers the concept of idealized learning environments, defined as "Havens." Various components of Havens are discussed that may facilitate comprehension, especially in science instruction. These components include: (1) the opportunity to learn in semantically rich contexts; (2) the availability of "mediators" who can guide learning; and (3) the importance of understanding how new knowledge can function as conceptual tools that facilitate problem solving. Three experiments were presented that suggest some of the advantages of learning in "Haven-like" environments. Two experiments were done with college students and one with junior high school students. The experiments involve very simple uses of instructional technology, yet they showed positive results. The results suggest that more sophisticated use of technology, especially computer-controlled interactive videodiscs, should have even greater benefits on comprehension and other forms of learning. Some videodisc-based Havens that are being developed at Vanderbilt University are described. (Author/TW)