The role of the printed answer in programmed instruction
George L. Geis, William Jacobs, Dwight Spencer, S. Vinther Nielsen · NSPI Journal · 1970
Abstract Using a variety of programmed materials, this series of studies showed that students observed available answers in the program far less than 100% of the time. Answer observing was found to be correlated with student error on the related frame. The view that the printed answer in a program is always a reinforcer for the preceding response(s) is severely questioned.