The author of this article presents his own explanation on the two types of conditioning--respondent and operant. He states that when withdrawal of a negative reinforcer is the contingency that increases the strength of the operant behavior, the stimulus will have a negative emotional response to the experimental chamber. However, when a positive reinforcer is used to strengthen the operant behavior, a positive emotional response will be conditioned to the stimulus of the operant chamber. To further this discussion, the author sketches an experimental apparatus and procedures with rats as the subject of the study.