If you’re a newcomer to ABA or if you’ve been hanging around behavior analysts for a while, you’ve probably noticed that BCBAs love the ABCs!  Making sense of the alphabet soup can sometimes get quite confusing…so enter Interact Therapy Services’ primer on the ABCs of ABA.

We begin today with the letter “A”.  A is for ANTECEDENT.


Cooper, Heron and Heward (2007) wrote the textbook known as the “White Book”, which is regarded by many behavior analysts as the premier authority on Applied Behavior Analysis.  They define antecedent as “an environmental condition or stimulus change existing or occurring prior to a behavior of interest”.  In plain language, an antecedent is anything that happens right before a behavior happens.

So, putting your hand under the hot faucet before you get burned?  Antecedent.  Seeing the approaching car that causes you to slam on the brakes?  Antecedent.  The squeaking of the pantry door opening that triggers the toddler to scream “cookie”? Antecedent.   Thinking about spiders eliciting a full-blown panic attack?  Antecedent.

These examples share a commonality.  In each situation, experiencing (feeling, seeing, hearing, thinking or otherwise sensing) the first occurrence caused the behavior to happen,  I couldn’t have gotten my hand burned (behavior) had I not put it under the hot faucet (antecedent).  You wouldn’t have slammed on the brakes (behavior) had you not seen an approaching car (antecedent).  Nathan, your toddler, wouldn’t have screamed “cookie” (behavior) had he not heard the pantry door squeak open (antecedent).  And Jessica wouldn’t have had that panic attack (behavior) had she not thought about spiders (antecedent).


One of the most important parts of the beahvioral intervention process is assessing for antecedents.   Behavior analysts believe that behavior NEVER occurs in isolation.  If you look hard enough, you’ll always find that some kind of environmental event caused the behavior to happen. 

One of our favorite sayings at Interact Therapy Services is “There is no such thing as no antecedent.”  Nothing is random.  People are intentional creatures and everything that we do has meaning.  Sometimes the antecedent can be very nuanced or very complex because humans are the most fascinating and intricate beings. In advanced behavior analysis, you can easily be working with antecedents that are several years old triggering behaviors of today.  For example, trauma is a very far-reaching antecedent that can shape a person’s behaviors and reactions for many decades to come.

It can be trickier to connect the dots when working with individuals with ASD.   The neurodiverse brain often interprets and reacts to environmental stimuli differently than the way a neurotypical brain would respond.


Since behavior change is at the heart of behavior analysis, it is critical to know the antecedents involved in the behavior that we are trying to change.  If A (antecedent) leads to B (behavior), changing A will certainly change B. We call interventions that manipulate antecedents to generate behavior changed “antecedent interventions”.

Antecedent interventions are one of the most user-friendly and powerful tools that ABA has to offer.  By simply changing the antecedents in a situation, the concerning behavior can be eliminated completely.

Here’s the magic (well, actually the science) of antecedent intervention in real life:

Michael, a 7-year-old boy with ASD, often had terrible tantrums immediately upon returning home from school.  After his BCBA carefully analyzed his day and assessed his behaviors, it was determined that Michael ate afternoon snack at 1:30 PM at school.  He had nothing else to eat until the school bus dropped him off at home at 4:15.   Michael had a limited verbal repertoire; it was too challenging for him to recognize and verbally express his hunger.  Michael’s BCBA suggested that Michael’s mom pack a filling snack for Michael to eat on the bus ride home.  Michael’s mom asked the bus aide to remind Michael about the snack.  After a few days of eating the additional snack on the bus, Michael’s tantrums disappear.

Clara, a 4th grader in a special education classroom, would hide under her desk at morning meeting.  When Clara’s BCBA performed a functional behavior assessment, she discovered that Clara’s spot in the meeting circle was next to the window.  The bright sunlight that flooded into the classroom was painful to Clara’s sensitive eyes.  Clara resumed her cheerful participation in morning meeting after her seat position was changed.


Antecedent interventions are a beloved and belittled technique in the behavior analyst’s toolbox.  Just as in the illustrations above, generally, antecedent interventions are easy-to-implement, long-lasting solutions to complex problems.  Little training is usually required to implement an antecedent intervention.  Additionally, most antecedent interventions are usually respectful, compassionate, and trauma-informed.  Win, win, win—right?

Not so fast!  At its essence, an antecedent intervention is a Band-aid, because it doesn’t create lasting change in the client.  Antecedent interventions are artificial manipulations of the environment because they do not teach clients important skills that are necessary to navigate adverse circumstances.  For example, with an extra snack alone, Michael will no longer be hangry—but has he learned to communicate effectively?  With a new seat, Clara is a cooperative student—but has she learned to access resources and problem-solve independently?  In the short-term, we may have solved the problem, but in the long-run, are we handicapping them?

Antecedent interventions are best when used as part of a comprehensive intervention package.  An antecedent intervention can resolve an emergency and restore sanity to struggling people.  But once the crisis has passed, it is important not to leave the job half-done, and to ensure that we are working together with the people involved to teach the skills and competencies needed for them to become as functional and independent as they can be!


A trusted ABA agency, staffed with experienced and skilled professionals, will create an individualized, seamless treatment program for your child.  Because your child’s challenges impact their lives in many ways, your child’s plan can and should include many different interventions. The gold-standard of ABA will always include a diverse and seamless treatment approach to help individuals with ASD and their families live their best lives.   At Interact Therapy Services, we carefully select all staff for their clinical knowledge, professionalism, expertise, and understanding of families and children.

At Interact Therapy Services, we offer in-home ABA therapy services to children and their families.  Our caring and committed professionals will work together with you to teach your child the skills that they need to progress and succeed.

To find out more about Interact Therapy Services, call 732.806.0804 for a free no-obligation phone consultation.  We look forward to helping you and your child!


Cooper, J. O., Heron, T. E., & Heward, W. L. (2008). Applied Behavior Analysis. Pearson/Merrill-Prentice Hall.

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