In some early attempts by psychologists to describe the basic learning process, the terms 'stimulus', 'response' and 'reinforcement' were introduced. In an educational setting, these (1)_____ could be defined as follows. When a teacher gives an (2)_____, or sets a problem, or asks a question, the pupil (3)_____ in some way, and the teacher then tells the pupil if he has responded correctly. The teacher's first action is called the (4)_____. The pupil's action, carrying out the instruction, or solving the problem, or answering the question, is (5)_____ the response. When the teacher tells the pupil his response is (6)_____, the bond between the stimulus and the response is strengthened and reinforcement is positive. If the response is incorrect, the bond is weakened, and reinforcement is (7)_____ Some psychologists laid great (8)_____ on the importance of reinforcement for continued learning. They (9)_____ that if a learner is not given information about his responses (feedback) he may not continue to respond. (10)_____, if his homework is not marked regularly, he will stop doing it. If in class, the answers he gives to the teacher's questions are (11)_____ or brushed aside, he will stop trying to give any. Educational psychologists are, (12)_____, moving away from this simple, early (13)_____ of the basic learning process. The effects of feedback, for example, are seen to be more (14)_____ than this description suggests. Feedback does not merely positively or negatively (15)_____ the stimulus-response bond. It may (16)_____ confirm previously learned meanings and associations, correct mistakes, (17)_____ misunderstandings and show how well or badly different parts of the material have been learned. Thus (18)_____ may have the effect of increasing the learner's confidence, backing up his previously (19)_____ knowledge, and showing him which items he has not (20)_____ grasped.