Cognitive psychology, artificial intelligence, and computer technology have advanced so much that it is feasible to build computer systems that are as effective as intelligent human tutors. Computer tutors have been developed for teaching students to do proofs in geometry and to write computer programs in the LISP language. (JN)

The process of forming operator schemata was studied in three experiments. In each experiment a greater amount of predictive information in a stimulus item increased the chance of selecting the operator accurately.