Event recording is simply a procedure for recording the occurrence of a behavior of interest. Skinner recognized the importance of precise recording of data when he studied animal operant behavior in the Skinner box. In most cases, the data were whenever an animal pressed a bar or pecked a key. He devised an event recorder called the cumulative recorder for just this purpose. The cumulative recorder produced graphs similar to that seen in Figure 1. This device was composed of a roll of paper that moved at a constant speed with a pen traveling across the paper. Whenever a response was emitted, a circuit was completed and an ink pen jumped up a unit of distance while the paper in the recorder continued to ...