Ian Tends to Be Very Shy About Participating in Class

Ian tends to be very shy about participating in class discussions. You decide to try to promote greater participation in class discussion by first smiling encouragingly at him when he merely looks interested in saying something, then smiling at him when he raises his hand, and then praising him when he actually makes a contribution. The technique you are using is referred to as

A) spontaneous recovery.
B) shaping.
C) extinction.
D) positive reinforcement.