What is Functional Communication in ABA? Teaching Kids What to Do Instead

Written by Tara Karen, M.S. Ed, BCBA, LBA.

When a child bites, hits, throws objects, or melts down, adults often focus on stopping the behavior. That makes sense- these behaviors are disruptive, sometimes dangerous, and hard to watch. But if we only focus on what we want a child to stop doing, we miss the more important question: what do we want them to do instead. This is the core idea behind functional communication training (FCT) in ABA, one of the most well-researched and effective interventions in ABA therapy and childhood support.

FCT doesn’t ask a child to simply stop doing something. It teaches them a better, more effective way to get what they need, and in doing so, it addresses the root of the problem rather than just the surface. In short- we teach a child what to do, instead of what not to do, because many times, children aren’t actually aware of what they should be doing, they only know what works for them.

Behavior as Communication

Before we can teach a replacement behavior, we have to understand what the original behavior is communicating. In ABA, or applied behavior analysis, this is called understanding the function(s) of the behavior — the reason it’s happening and what it’s getting the child.

Most challenging behaviors serve one or more of these functions:

• Access/Tangible: The child wants something (a toy, food, an activity)
• Escape: The child wants to avoid or end something (a task, a sensory experience, a transition)
• Attention: The child wants social connection or a response from another person
• Sensory/Automatic: The behavior itself provides a desired sensory experience

Here’s the key insight: a behavior that looks “bad” is often working extremely well for the child. Screaming gets attention. Throwing a plate ends the meal. Biting during a hair-brushing routine makes the brushing stop. From the child’s perspective, these are successful communication strategies, and why would they change what is working? Punishing or suppressing the behavior without addressing the root function is like unplugging a smoke detector instead of looking for the fire. The alarm stops. The problem doesn’t.

What Is Functional Communication Training?

Functional communication training is a structured approach to teaching children more appropriate ways to communicate their needs-ways that serve the same function as the challenging behavior, but are safer, more effective, more interactive, and way less dangerous and disruptive.

Developed by Dr. Edward Carr and Mark Durand in the 1980s, FCT has been replicated across hundreds of studies and across diverse populations, including children with autism, intellectual disabilities, and other developmental differences. The evidence base is strong and consistent: when children are taught meaningful replacement behaviors, challenging behaviors decrease — often dramatically.

The replacement behavior must meet several criteria to be effective:

It must serve the same function

If a child bangs on the table to get a snack, teaching them to say “snack please” or hand over a picture card serves the same access function. Teaching them to sit quietly with their hands down does not — it ignores what they were actually trying to communicate, and will be ineffective and stress inducing for everyone.

It must be easier than the challenging behavior

This is often overlooked. If the replacement behavior requires more effort, more skill, or produces results less reliably than the original behavior, the child will default back to what works. The new communication form has to be a better deal. This is why we will usually teach a sign or picture even for children “with language” because sometimes accessing language is too frustrating or difficult when they are stressed.

It must be something the child can actually do

The form of communication needs to match the child’s current abilities. For a child without verbal language, teaching a spoken phrase isn’t realistic yet. But teaching a gesture, a picture exchange, a sign, or a device-based response might be. This is not a time to expand communication forms or length of responses, this is a time to teach the better way to get what they would like.

Common Replacement Behaviors in ABA Across Different Functions

For access (wanting something):

• Pointing or reaching
• Handing over a picture or symbol card
• Saying or signing “more,” “want,” or the item’s name
• Pressing a button on a speech-generating device

For escape (wanting to avoid something):

• Saying or signing “break,” “no,” or “all done”
• Handing over a “break” card
• Raising a hand to signal needing a pause
• Using a gesture to indicate “stop”

For attention:

• Tapping someone’s arm
• Saying a name
• Waving
• Using a greeting or request for interaction

The specific form matters less than the match to function and the child’s current skill level. Studies actually show that using 2 or more forms of communication responses benefits the child and does not hinder speech.

Teaching a replacement behavior doesn’t happen in isolation. The environment needs to be set up to support success, and adults need to respond consistently to the new communication form.

It is important to note that during FCT, honoring the communication response is more important than teaching toleration or delay.  When dangerous or disruptive behaviors have been greatly reduced and the communication response is consistent- that is the time to start working on toleration or denial or delayed access (and in small doses). Once a child can more effectively be understood, we see that those “behaviors” occur less frequently also.

Tips for Successful Functional Communication Training

Some tips for success:

Be responsive — immediately. When a child uses their replacement behavior, they need to get what they’re asking for quickly and reliably. If they use a “break” card and the adult doesn’t honor it, the child learns that the new strategy doesn’t work. They go back to what does.

Don’t wait for the meltdown. FCT is most effective when the replacement behavior is taught proactively, before the child reaches a crisis point. Practice the new communication form during calm moments, during play, and across multiple settings and partners.

Respond to early signals. Children often communicate in escalating ways — a small whimper before a scream, a push before a bite. Learning to catch and respond to the early, lower-intensity signals helps prevent the behavior from escalating and reinforces the idea that communication works.

Reduce barriers to the replacement behavior. If a child is expected to use a picture card, the card needs to be easily accessible — not in a drawer, not across the room, not buried under other materials.

Conclusion: A New Approach to Challenging Behaviors

Challenging behavior is not a character flaw. It’s a communication attempt from a child who hasn’t yet found a better way to get their needs met. Functional communication training starts from that place of understanding and asks a fundamentally different question than traditional behavior management: not “How do we stop this?” but “What is this child trying to tell us, and how can we help them say it better?”