Contained in this monograph is a review and synthesis of developmental psychology and learning theory, with major emphasis upon applications of the developmental perspective to environmental education curriculum and instruction. Based upon a summary of the work of Piaget and his followers, a learning readiness axis is proposed. Also examined are how selected instructional implications of learning theory, such as Gagne's learning hierarchies, can relate to cognitive development. Modules developed by the Far West Laboratory for Educational Research and Development are drawn upon to illustrate the application of the psychological constructs discussed to the learning of environmental concepts. Both subject matter and process skills are viewed as subordinate learning hierarchies that lead to an understanding of the environmental system being studied. To be consistent with the developmental readiness of most learners, it is recommended that educators prepare learning activities appropriate for students in the transition between the representational (concrete) and formal operations periods. Provided in the appendix is a review of current developmental research. (WB)