1)The selection and arrangement of educational content based on principles of human learning (Taber et al., 1965). The student progresses in steps from one level of difficulty to the next. Reinforcement is primarily in the form of confirmation of correct responses.

2) Instruction which is broken down into steps, each of which requires the student to respond. Branching programs have a short passage to study and then a multiple-choice item for each choice, the students are sent to a different section, either telling them they are correct (and giving the next step) or explaining why they are wrong and sending them back to try again. Linear programs have very short items, called frames, which typically have a sentence to be completed or require the students to draw or construct something. The students are supposed to respond and then uncover the answer. They then proceed to the next item. The amount of active responding required in linear programs is greater than that in branching. B.F. Skinner wrote the first linear program as an attempt to shape the behavior of the student.