ABC’s of Behavior

How to Identify the Function of the Behavior?

By this point, you may be asking yourself, "How in the world do I tell what the function of the behavior is?" when faced with a difficult, challenging behavior. Or perhaps you notice someone engaging in a wonderful behavior that you want to see more of, but you want to know the function so that you can reinforce it appropriately.

The Three-Term Contingency

In Applied Behavior Analysis (ABA), a BCBA or other practicing clinician will use the three term contingency to help them determine what the function of the behavior is. The three term contingency is represented by the letters A.B.C. and include the following:

1. Antecedent
2. Behavior
3. Consequence

The antecedent refers to what happens right before a behavior, and the consequence refers to what happens right after the behavior occurs.

How to Understand Function

Typically, you'll want to look at the antecedent to determine what the function of the behavior is. For example, if you told your child to sit down to do their homework and as a response your child screams and throws the chair, because the antecedent was telling them to do something (e.g. homework) You know that they are trying to escape the task, and therefore the function of screaming and throwing the chair is escape maintained.

How to Use Consequence

Clinicians will use the consequence to determine whether or not a behavior is being reinforced or punished. As a reminder, reinforcement is anything that increases the behavior, and punishment is anything that decreases a behavior.

For example, if after your child screams and throws the chair you let them take a break and go watch some TV, and then next time you ask them to go do their homework they scream and throw another chair, you know you've reinforced the behavior because the consequence (e.g. giving them a T.V. break) rewarded their escape-maintained behavior, which led to the behavior occurring again in the future.