Two experiments tested the general question of whether a more "natural" artificial light (Vita-Lite) would have any different effects on classroom behavior and the ability to study than would a traditional (cool-white) light source. Fifty-nine undergraduates took part in the first experiment that utilized an 8-week counterbalanced design. Videotapes of classroom behavior and post-seminar questionnaires indicated no significant differences in variables dealing with classroom interaction, seminar effectiveness and mood. A follow-up questionnaire did show however, that upon direct appraisal, the Vita-Lite was perceived as stronger, more stimulating, brighter and more harsh than the cool-white light source that was considered softer and more relaxing. Using a similar research design, a second experiment showed that on physiological measures, most subjects showed less fatigue after a study session under the Vita-Lite than under the cool-white light. No significant differences in subjective estimates of fatigue were identified. A newly designed graphic technique was used to illustrate and support the data analysis and implications were drawn about the use of environmental information by educators and designers. A 26-item bibliography and appendices of related material are included. (Author)