People who use behavior modification define their target behavior carefully, and directly observe and record the behavior. In this way, they can document whether the behavior has indeed changed when a behavior modification procedure is implemented. The primary tool used to document behavior change is the graph.
A graph is a visual representation of the occurrence of a behavior over time. After instances of the target behavior are recorded (on a data sheet or otherwise), the information is transferred to a graph. A graph is an efficient way to view the occurrence of the behavior because it shows the results of recording during many observation periods.
Behavior analysts use graphs to identify the level of behavior before treatment and after treatment begins. In this way, they can document changes in the behavior during treatment and make decisions about the continued use of the treatment. The graph makes it easier to compare the levels of the behavior before, during, and after treatment because the levels are presented visually for comparison. It is easy to see that the frequency of the behavior is much lower during treatment (competing response) than before treatment (baseline). This particular graph is from a student’s self-management project. The student’s target behavior involved biting the insides of her mouth when she studied. She recorded the behavior on a data sheet each time it occurred. After 10 days of recording the behavior without any treatment (baseline), she implemented a behavior modification plan in which she used a competing response (a behavior that is incompatible with mouth-biting and interrupts each occurrence of mouth-biting) to help her control the mouthbiting behavior. After implementing this competing response procedure, she continued to record the behavior for 20 more days. She then recorded the behavior four more times, after 1, 5, 10, and 20 weeks. The long period after treatment has been implemented is called the follow-up period. From this graph, we can conclude that the mouth-biting behavior (as recorded by the student) decreased substantially while the student implemented the treatment. We can also see that the behavior continued to occur at a low level up to 20 weeks after treatment was implemented.
Components of a Graph
In the typical behavior modification graph, time and behavior are the two variables illustrated. Each data point on a graph gives you two pieces of information: It tells you when the behavior was recorded (time) and the level of the behavior at that time. Time is indicated on the horizontal axis (also called the x-axis, or the abscissa ), and the level of the behavior is indicated on the vertical axis (also called the y-axis, or the ordinate ). The frequency of mouth-biting is indicated on the vertical axis, and days and weeks are indicated on the horizontal axis. By looking at this graph, you can determine the frequency of mouth-biting on any particular day, before or after treatment was implemented. Because follow-up is reported, you can also see the frequency of the behavior at intervals of up to 20 weeks.
▪Six components are necessary for a graph to be complete.
▪The y-axis and the x-axis. The vertical axis (y-axis) and the horizontal axis (x-axis) meet at the bottom left of the page. On most graphs, the x-axis is longer than the y-axis; it is usually one to two times as long
▪The labels for the y-axis and the x-axis. The y-axis label usually tells you the behavior and the dimension of the behavior that is recorded. The x-axis label usually tells you the unit of time during which the behavior is recorded. In Figure 3-3 , the y-axis label is “Hours of Studying” and the x-axis label is “Days.”
Thus, you know that the hours of studying will be recorded each day for this particular person.
▪The numbers on the y-axis and the x-axis. On the y-axis, the numbers indicate the units of measurement of the behavior; on the x-axis, the numbers indicate the units of measurement of time. There should be a hash mark on the y-axis and the x-axis to correspond to each of the numbers. In Figure 3-4 , the numbers on the y-axis indicate the number of hours the studying behavior occurred, and the numbers on the x-axis indicate the days on which studying was measured.
▪Data points. The data points must be plotted correctly to indicate the level of the behavior that occurred at each particular time period. The information on the level of the behavior and the time periods is taken from the data sheet or other behavior-recording instrument. Each data point is connected to the adjacent data points by a line .
▪Phase lines. A phase line is a vertical line on a graph that indicates a change in treatment. The change can be from a no-treatment phase to a treatment phase, from a treatment phase to a no-treatment phase, or from one treatment phase to another treatment phase. A phase is a period in which the same treatment (or no treatment) is in effect. The phase line separates baseline (no treatment) and treatment phases. Data points are not connected across phase lines. This allows you to see differences in the level of the behavior in different phases more easily.
▪Phase labels. Each phase in a graph must be labeled. The phase label appears at the top of the graph above the particular phase. Most behavior modification graphs have at least two phases that are labeled: the notreatment phase and the treatment phase. “ Baseline ” is the label most often given to the no-treatment phase. The label for the treatment phase should identify the particular treatment being used. The two phase labels are “Baseline” and “Behavioral Contract.” The behavioral contract is the particular treatment the student is using to increase studying. Some graphs have more than one treatment phase or more than one baseline phase.