You will be receiving a cumulative record for some of your experiments. This should be included in the applicable laboratory report. It will however require explanation.

The cumulative record provides a graphic representation of the subject’s bar pressing behavior.

The x-axis (0-50) is the number of minutes. The y-axis (0-100) is the number of responses made by the subject. A flat line indicates that the subject is not responding. A slope indicates responding. The steeper the slope, the higher the response rate. The pips (hairlines) indicate reinforcement.

An example of a cumulative record  follows. It is for an Extinction and Spontaneous Recovery Experiment. This is an example of an explanation for this cumulative record:

The first thirteen minutes represent a period of continuous reinforcement. For the first five minutes, there is an almost straight line on the cumulative record, which represents little responding by the subject, who made only six responses during this time. The steep upward slope (minutes six through thirteen) is indicative of steady responding. The first extinction trial began in minute fourteen. The increase in slope indicates an increase in the rate of responding during this minute, and is evidence of extinction burst. The rate of responding then declined, and extinction was achieved in the following two minutes, as can be seen by the straight line indicating that no responses were made. The extinction criterion for this experiment was two minutes of no responding.

The cumulative record also shows a straight line for the period during which the subject was returned to his home cage. Responding began again in minute twenty-six when the subject was returned to the operant chamber. Responding continued for four minutes after which there is again a straight line indicating no responses, and a second extinction. The straight line continues through the period during which the subject spent ten minutes in the home cage. Then, at minute forty-five, the straight line on the cumulative record is interrupted, indicating a small number of responses at the beginning of the third extinction phase. The straight line then continues, indicating that extinction has taken place for the third time. The responses made at the beginning of the second and third extinction trials are evidence of spontaneous recovery.