Learners should also be allowed to proceed at their own individual rate. Skinner's ideas have been said to have their roots in the work of E.L. Thorndike and Sidney L. Pressey, known as the precursors of the programmed instruction movement. Pressey did develop learning machines, but felt that the educational world was not yet ready for them and discontinued his work in this area. The machines, though, had a comeback based on Skinner's ideas. Units are placed in definite sequence and students are required to demonstrate mastery of each unit, and not allowed to move on until mastery is evident.
Immediate feedback is given by way of quizzes, tutors, etc.
The time needed would be dependent upon the quality of instruction given. John C. Flanagan headed the development effort. Based on learning objectives developed by both the teacher and student, together. Development headed by Herbert Klausmeier. Gordon Pask-made use of computer technology to teach such skills a card punching and object tracking.