Cognitive learning related to the environment has typically been subsumed as a part of instruction in the more traditional areas of the secondary school curriculum, in particular in science and/or social studies classes. This digest contains a review of a number of studies dealing with cognitive learning in the environment, investigating the advantages of field instruction for the purposes of concept and content learning. Particular attention is given to efforts in the biological and earth sciences, the subject areas in which much instruction in the scientific aspects of the environment is focused. The relative sparsity of research literature dealing with cognitive learning in the environment is noted. It is suggested that this is an indication that little cognitive instruction in secondary schools takes place in field settings. However, those studies which have been reported tend to indicate that field-based instruction is a teaching technique worthy of additional well-designed implementation by practitioners, along with additional, extensive rigorous study by educational researchers. (TW)