Applied Behavior Analysis (ABA) is the application of the science of behavior. The science and its practice have been around for many decades and has its roots in basic, laboratory research. Behavior analysts are the individuals that practice ABA. Behavior is what interests behavior analysts. This behavior can be either human or nonhuman. Some behavior analysts work with animals of all varieties. Regardless of the performer (i.e., the person or animal performing the behavior), behavior analysts are interested in behavior.

ABA focuses on analyzing behavior in terms of the context that it occurs. That is, behavior analysts are equally interested in the environment where behavior occurs as they are with the behavior itself. When analyzing behavior, behavior analysts frequently look at antecedents to the behavior and consequences of the behavior.

Antecedents can be, and sometimes are, a multitude of events and environmental characteristics that occur before behaviors happen. For example, if you were sitting in a classroom all of the characteristics of that classroom (e.g., the room temperature, the noise level in the room, the smell, all of the students, the conversation of a specific student, etc.,) can be potential antecedents to behavior. In analyzing antecedents, the behavior analyst can begin to focus on the things that trigger behavior. That is, the stimuli that occasion behavior. He/she is now developing conditional probabilities for when a behavior is more likely or less likely to occur. If you have ever said “so and so behaves different when they are in one location (e.g., home) than they do when they are in another location (e.g., school) or they behave different with one person than they do with another person”, you are getting at the heart of this issue.

Consequences are the events that come after or the outcomes of a behavior and can also come in a multitude of types. Consequences can be events that occur for the performer of the behavior or be events or occurrences that occur to others. It is important to look closely at all potential consequent events when analyzing behavior. When analyzing consequences, the behavior analyst can develop some hypotheses as to why a behavior is occurring. That is, what are the potential reinforcing consequences for that behavior. Determining these consequences assists the behavior analyst in determining the function that a behavior serves for a person.

Considering the antecedents, behavior, and consequences is sometimes referred to as a sequence analysis or also as a three-term contingency. There are other things to consider and they are often referred to as the fourth-term. These are setting events or motivating operations. Considering all four of these is an important analysis if behavior analysts are interested in changing behavior. Current practice in ABA relies in behavior analysts doing these types of analyses and then supplementing the performer with alternative, more acceptable behaviors. These behaviors are then taught to the performer (i.e., reinforced) with the intent that the new behaviors will replace the old, undesirable behaviors.