In this report, the effectiveness of prototypes of interactive learning environments (ILEs) is compared with printed learning environments or traditional face-to-face lectures. The learning content for all conditions was a course on inferential statistics for first-year college students. In the learning materials, a clear distinction was made between the basic content and embedded support devices (ESDs) that are expected to support learning. The prototypes differed in the extent to which they supported interactivity in manipulating the ESD and the degree of discernability of the ESD. In a large empirical study involving 502 Belgian college students, ILEs were compared with learning environments based on printed materials and traditional lectures. Results indicate that there are no differences in learning outcomes when the conditions are compared. They also show the role of ESDs and the significant aspects of individual differences among students on study outcome. Three tables summarize study findings. (Contains 36 references.) (Author/SLD)