Talk the Talk: Antecedent-Behavior-Consequence

Talk the Talk: Antecedent-Behavior-Consequence

In the field of Applied Behavior Analysis (ABA), we analyze not only behaviors targeted for increase or decrease, but the environmental cues and contexts that surround them as well.  ABA uses something called the three-term contingency, or the ABCs of behavior, to examine how behaviors are evoked by certain aspects of the environment. We then use those data to evaluate how consequences will predict the future occurrence of the behavior.  The letters in this three-term contingency stand for antecedent, behavior, and consequence (ABC).  Keep reading for a deeper look into each of these terms and how they can be used to determine the function of a behavior. 


Technically speaking, the antecedent is the state of the environment before a specific behavior occurs. The environment often contains several variables that can influence the likelihood a target behavior will occur, including the reinforcing properties of a specific consequence.  

To put it simply, the antecedent is the event, circumstance, or action that happens immediately before a behavior.  In other words, it’s what happens in the environment IMMEDIATELY BEFORE a behavior is emitted. 

Let’s look at a real-life example: Your cat is sitting on the couch and you are petting him. He suddenly swipes at your hand and scratches you. The antecedent in this situation is you petting your cat. 

When observing and recording antecedents, it’s important to look at what happens in the environment IMMEDIATELY before a behavior is emitted.  It’s easy to make mistakes if more than one change takes place within the environment.  For example, say your cat is sitting on the couch and you’re petting him. Suddenly a loud bang happens when your partner drops a book on the floor. Your cat swipes at your hand and scratches you. The antecedent in this situation is NOT petting your cat. Instead, it’s the loud noise made by the book, as it happened right before the cat scratched you. 


Technically defined, a behavior is an interaction between an action of an organism (i.e., a living thing) and its environment.  

A simpler way to define a this is anything the target person, animal, or any other living thing says or does.  It can be simple and observable, such as throwing a ball or saying a word.  It can also be complex and unobservable such as thoughts (also called private events, but we will get to that in a later post!). 

Remember the cat from earlier?  Now, say your cat is sitting on the couch, and you are petting him like before. He suddenly swipes at your hand and scratches you. The behavior in this situation is your cat scratching you. 

Behaviors must pass something called the “Dead Man’s Test” to be considered a behavior.  The Dead Man’s Test says that if a dead man can do it, it is NOT a behavior.  To illustrate this, let’s go back to when you were petting your cat on the couch and suddenly a loud bang happens when your partner drops a book on the floor. Your cat swipes at your hand and scratches you. The behavior in this situation is NOT sitting on the couch, as this doesn’t pass The Dead Man’s Test (a dead man can definitely sit on a couch!). Instead, it’s the cat scratching you, as a dead man can’t do it. 


A consequence is described as the state of the environment after a behavior occurs. In other words, it’s a description of how the environment changed after a behavior occurred. If something is added to the environment, such as getting attention for scoring the winning goal in a soccer game or getting a reprimand for teasing a friend, the term “positive” is used (i.e., positive reinforcement or positive punishment). If something is removed from the environment, such as the relief from itching after scratching a bug bite or not being allowed to play video games after hitting your brother, the term “negative” is used (i.e., negative reinforcement or negative punishment). Similar to the antecedent, a consequence can also increase or decrease the likelihood a target behavior will occur in the future. 

It is often assumed that the term consequence indicates something negative has or will occur after a behavior (for example reprimands or timeouts).  This is a common misconception, as consequence includes all events that occur following a behavior, whether they be “good” or “bad.” 

Now, back to our example with that pesky cat. After he scratches you, you stop petting petting him, shout some choice words, and go get a Band-Aid. The consequence of the cat’s scratching is not just a cut on your hand, but also your behavior of engaging in first aid care and, probably most important to the cat, him escaping your petting. 

Here are a few other examples of the three-term contingency (or ABCs of behavior): 

By examining all aspects of the environment where behavior occurs, the ABA team can identify the function each behavior serves.  By addressing all of these factors, the team can then implement an intervention that provides replacement behaviors that are functionally equivalent (or has the same effect on the situation) to the behaviors targeted for decrease.