Parents often come to AAC because they want their child to communicate. But many discover an unexpected benefit along the way. The hitting decreases. The biting becomes less frequent. The meltdowns, while not gone entirely, happen less often and resolve faster.
This isn't coincidence, and it isn't wishful thinking. There's a strong body of research connecting communication access to behavior reduction. When children gain the ability to express what they need, want, and feel, many of the behaviors that were serving as communication decrease on their own.
Here's what the research says, how it works, and what the timeline actually looks like.
The Frustration-Communication Link
Before looking at studies, it helps to understand why challenging behaviors happen in the first place.
Behavior analysts use the term "function" to describe why a behavior occurs. Most challenging behaviors in children with communication difficulties serve one of four functions:
- Escape. The child wants to stop or avoid something. (Hitting when it's time to brush teeth.)
- Attention. The child wants someone to notice them or interact. (Screaming until a parent comes over.)
- Access to tangibles. The child wants a specific item or activity. (Grabbing toys from others.)
- Sensory. The behavior provides a physical sensation the child seeks. (Rocking, hand-flapping.)
For children with limited speech, the first three functions are directly tied to communication. The child is trying to say "stop," "look at me," or "I want that," but they don't have the words. So they use behavior instead.
Carr and Durand (1985) were among the first to demonstrate this formally. In their landmark study on functional communication training (FCT), they taught children specific phrases that served the same function as their challenging behaviors. When a child who hit to escape tasks was taught to say "help me" or "I need a break," the hitting decreased dramatically. The child hadn't been defiant. They'd been communicating the only way available to them.
What the Research Shows
Carr and Durand (1985): Functional Communication Training
This foundational study established the principle that drives most modern behavior support plans. Carr and Durand worked with children whose challenging behaviors were maintained by either escape from tasks or attention from adults.
They taught each child a communicative response that matched the function of the behavior. For escape-maintained behaviors, children learned to say "I don't understand" or "Help me." For attention-maintained behaviors, they learned "Am I doing good work?"
Results: challenging behaviors dropped to near-zero levels when the children used the replacement phrases. The behaviors returned briefly when the phrases were blocked, confirming that communication was doing the work.
The takeaway: if you give a child an effective way to get what they need through words, the behavior that was getting them the same thing becomes unnecessary.
Walker and Snell (2013): Meta-Analysis
Walker and Snell conducted a comprehensive meta-analysis of studies on communication-based interventions for people with intellectual disabilities. They looked at research spanning decades to determine whether teaching communication skills reliably reduced challenging behaviors.
Their findings were strong:
- Communication-based interventions produced significant reductions in challenging behavior across studies
- The most effective interventions matched the communicative function of the behavior. Teaching "all done" worked best for escape behaviors. Teaching "I want" worked best for access behaviors.
- The effects were consistent across age groups, disability types, and settings
This meta-analysis is important because it shows that the Carr and Durand findings weren't a one-time result. The pattern holds across dozens of studies, populations, and years of research.
Drager, Light, and McNaughton (2010): Early AAC Intervention
Drager and colleagues focused specifically on young children with complex communication needs. They reviewed studies on AAC intervention for children under six and found that:
- Early AAC intervention was associated with improvements in communication and language
- Children who received AAC showed reduced frustration and fewer challenging behaviors
- The benefits were strongest when AAC was introduced early, before behavior patterns became entrenched
This last point is critical. The longer a child relies on behavior to communicate, the more habitual those patterns become. Introducing AAC early means the child learns communicative alternatives before the behaviors are deeply established.
Mirenda (1997): Communication and Behavior Support
Mirenda published an influential review arguing that AAC should be a core component of positive behavior support plans for individuals with disabilities. She outlined the theoretical and empirical case for why communication access reduces challenging behavior and argued that behavior support without communication support is incomplete.
Her framework is simple: if you identify the communicative function of a behavior and then teach a communicative replacement through AAC, you address the root cause rather than just managing the symptom.
How It Works in Practice
Research findings are one thing. What does this look like in daily life?
Example 1: The child who hits at mealtimes
The behavior: A five-year-old hits and pushes their plate away at dinner. Parents interpret this as defiance or pickiness.
The function: Escape. The child doesn't want what's being served and has no way to say so.
The AAC intervention: The child is taught to tap "no," "don't want," and "different" on their device. When they use these words, the parent responds. "Okay, you don't want the peas. What do you want instead?"
What happens: The hitting decreases because "don't want" achieves the same result with less effort and better outcomes. The child actually gets to choose an alternative, which is better than just pushing the plate away and getting nothing.
Example 2: The child who screams during transitions
The behavior: An eight-year-old screams and drops to the floor when asked to stop playing and get ready for bed.
The function: Escape from the transition, and possibly access (wanting to keep playing).
The AAC intervention: The child learns "more time," "wait," and "almost done" on their device. The parent introduces a visual timer alongside the AAC. "You have five more minutes. When the timer goes off, you can say 'all done' and we'll start bedtime."
What happens: Transitions become negotiable rather than sudden. The child has some control over the process. Screaming decreases because they have tools to manage the moment.
Example 3: The child who bites during group activities
The behavior: A three-year-old bites other children during playgroup when they take her toys.
The function: Protest and access. She wants the toy back and wants the other child to stop.
The AAC intervention: She is taught "mine," "stop," and "my turn" on her device. The supervising adult models these words in the moment. "You want that toy. Say mine. Say my turn."
What happens: With consistent modeling and responsive adults, the biting decreases. She discovers that "mine" said through the device gets an adult's attention and intervention faster than biting does.
The Timeline: What to Expect
One of the biggest questions parents have is: how long until we see behavior changes?
The honest answer is that it varies. But research and clinical experience suggest a general pattern.
Weeks 1 to 2: Exploration
The child is learning the device. Behavior changes are minimal. You're doing most of the modeling. Don't expect behavior reduction yet. This is the learning phase.
Weeks 2 to 4: First signs
If you're modeling consistently and honoring the child's communication attempts, you'll start to see small moments where the child uses a word instead of a behavior. These moments may be inconsistent. A child might use "stop" at the table but still hit at the park. That's normal. New skills don't generalize instantly.
Months 1 to 3: Gradual decrease
As the child becomes more fluent with protest and request words, you'll notice a gradual decrease in the behaviors those words replace. This isn't a sudden disappearance. It's a trend. Bad days still happen. But the overall trajectory is downward.
Months 3 to 6: New normal
For many families, this is when the shift becomes clearly noticeable. The child defaults to their device for protest and requests more often than not. Challenging behaviors still occur but are less intense and resolve more quickly. The child recovers faster from frustration because they have tools to express what's wrong.
Important caveats
Behavior may temporarily increase. When a child is learning a new communication skill, there's sometimes an "extinction burst." The old behavior gets worse briefly before it gets better. This happens because the child is testing whether the old strategy still works. Stay consistent. Model the AAC alternative. The burst passes. One specific behavior that worries many families during this phase is device throwing. If your child throws or pushes away the AAC device, our guide on what to do when your child throws their AAC device covers why it happens and how to respond.
Not all behavior is communication. Some behaviors are sensory-seeking, pain-related, or habitual. AAC won't address behaviors that aren't communicatively motivated. If behavior doesn't decrease after consistent AAC use, the function may be something other than communication, and a behavior specialist can help determine next steps.
AAC alone isn't enough. The communication tool needs communication partners who respond to it. If a child taps "stop" and nobody responds, the device is useless. Responsive adults are the critical ingredient.
What This Means for Families
If you're dealing with challenging behaviors and your child has limited speech, AAC is not just a communication tool. It's a behavior support strategy. The research supports this. Clinical practice confirms it. And thousands of families have lived it.
You don't need to choose between "working on communication" and "working on behavior." They're the same thing. Teaching a child to say "stop" is teaching them not to hit. Teaching "I want" is teaching them not to grab. Teaching "all done" is teaching them to manage transitions.
The behaviors that exhaust you are your child's way of telling you they need better tools. AAC provides those tools.
Download SabiKo free and give your child the words that replace the behaviors.
References
- Carr, E.G., & Durand, V.M. (1985). Reducing behavior problems through functional communication training. Journal of Applied Behavior Analysis, 18(2), 111-126.
- Walker, V.L., & Snell, M.E. (2013). Effects of augmentative and alternative communication on challenging behavior: A meta-analysis. Augmentative and Alternative Communication, 29(2), 117-131.
- Drager, K.D.R., Light, J., & McNaughton, D. (2010). Effects of AAC interventions on communication and language for young children with complex communication needs. Journal of Pediatric Rehabilitation Medicine, 3(4), 303-310.
- Mirenda, P. (1997). Supporting individuals with challenging behavior through functional communication training and AAC: Research review. Augmentative and Alternative Communication, 13(4), 207-225.