AbstractIn spite of the fact that psychologists have been investigating learning for many years, we still have no completely satisfactory theory of learning that will permit us to exert precise control over all the variables that exist in a learning situation. In fact, some people would argue that we have not even identified all the variables. We have no good idea of what is involved in concept formation, and we do not know how to guarantee that learning will generalize from the training situation to the job situation. In spite of these gaps in our theories, however, some principles of teaching have evolved over the centuries. Much of the excitement about the method of programmed learning stems from the fact that it provides some new ways for implementing these teaching principles.