Illustrative Example/Nonexample Pair #1: The Importance of an Increase in the Level of the Behavior
Example of positive reinforcement of smiling:
Stephan and Cody were two mentally disabled boys who seldom smiled at other people. Dr. Hopkins used a procedure in which he would take them for walks, and if they smiled at passers by, he would give them some pieces of M & M's candy. This procedure caused Stephan and Cody to smile much more often than they had before.
Nonexample of positive reinforcement of smiling:
Stephan and Cody were two mentally disabled boys who seldom smiled at other people. Dr. Hopkins used a procedure in which he would take them for walks, and if they smiled at passers by, he would give them some pieces of M & M's candy. Stephan and Cody ate the candy quickly.
The first item is an example of positive reinforcement. First, a consequence was presented dependent upon the target behavior. The candy was dependent on smiling because there was an if-then relationship between smiling and candy: If smiling occurred, candy was presented; but if no smiling occurred, no candy was presented. Second, there was an increase in the level of smiling. Third, the increase in the level of smiling was due to the relationship between smiling and candy.
The second item is not an example of reinforcement because there is no mention of an increase in the level of the target behavior. There must be an increase in some measure of the behavior in order to say that reinforcement has occurred.
Source: Hopkins, B. L. (1968). Effects of candy and social reinforcement, instructions, and reinforcement schedule learning on the modification and maintenance of smiling. Journal of Applied Behavior Analysis, 1, 121-129.