What Is Functional Communication Training in ABA Therapy?
Functional Communication Training (FCT) is an Applied Behavior Analysis (ABA) intervention that teaches a learner to use a socially appropriate communication response in place of an interfering behavior that serves the same function. If a learner screams to escape a non-preferred task, FCT teaches them to say or sign “break” instead. If a learner hits to get a parent’s attention, FCT teaches them to tap the parent’s arm. The new communication response earns the same outcome the interfering behavior was producing—and because the new response is more efficient or socially acceptable, the interfering behavior tends to decrease as the communication response is reinforced.
FCT was developed by Edward Carr and V. Mark Durand in the mid-1980s and has since become one of the most heavily researched interventions in behavior analysis. It rests on a foundational insight from ABA: interfering behavior almost always serves a function for the learner. Rather than trying to suppress the behavior through aversive consequences, FCT teaches a better way to accomplish the same goal. The intervention depends on the team having a clear understanding of the function of the behavior, typically determined through a functional behavior assessment.
Research on FCT is robust. According to a 2025 meta-analysis of FCT for young children with autism, published on PubMed Central at the National Institutes of Health, FCT demonstrates large effects for reducing challenging behavior and moderate-to-large effects for increasing replacement behavior across the studies analyzed. The authors note that FCT continues to meet evidence-based practice criteria for young children with autism spectrum disorder.
FCT can use any communication modality—spoken words, manual signs, picture exchange, AAC devices, gestures. The behavior analyst selects the modality that fits the learner’s current abilities and the environment where the new communication will need to work. Behavior technicians then teach and reinforce the new response across daily sessions, building it into a robust replacement for the interfering behavior. The goal is for the new response to be easier and more efficient than the interfering behavior it’s replacing, so the learner has a reason to use it.
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Examples of Functional Communication Training in ABA Therapy
Example 1: Teaching a verbal request to replace screaming
A behavior technician is working with a four-year-old client who screams to gain a parent’s attention. A functional behavior assessment confirms that the screaming is reinforced by the parent immediately turning to comfort the learner. The behavior analyst designs an FCT plan: the technician and parents teach the learner to tap the parent’s arm and say “Mom” instead. When the learner uses the new response, the parent turns and engages right away. When the learner screams, the parent waits a few seconds and prompts the appropriate response if needed. Within a few weeks, the learner is using the verbal request consistently and the screaming has dropped to near zero. For more on this kind of work, see our blog on addressing aggressive behaviors in children.
Example 2: FCT with picture exchange for escape from demands
A behavior analyst works with a six-year-old client who engages in interrupting behavior—flipping the table and dropping to the floor—during difficult academic tasks. The function is escape. The behavior technician teaches the learner to hand a “break” card to the technician when they want to pause the task. When the card is handed over, the task pauses for two minutes. When the learner flips the table or drops to the floor, the task continues without comment. The card-handing response earns the same escape the interfering behavior was producing, but in a way that’s safer and more communicative.
Example 3: FCT using AAC for a minimally verbal learner
A behavior analyst designs an FCT program for an eight-year-old client who is minimally verbal and uses self-injury—slapping their face—to request preferred items. The team teaches the learner to use a speech-generating device to request items by pressing icons for “music,” “snack,” and “outside.” Each device press is reinforced immediately with the requested item. The therapist and behavior technician work together across home and clinic settings to build fluency with the device. Over months, self-injurious requests decrease as the AAC requests take their place. For more on AAC and communication for nonspeaking learners, see our blog on what is nonverbal autism: dispelling the myths.
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Why Is Functional Communication Training Important in ABA?
FCT matters because it reframes how the team thinks about interfering behavior. Rather than treating the behavior as something to be suppressed, FCT treats it as communication that hasn’t yet found a more effective form. The intervention’s success rests on a respectful premise: the learner is trying to accomplish something legitimate, and the team’s job is to teach a better way to accomplish it. That framing changes the conversation between clinical teams and families about what interfering behavior is and what to do about it.
The procedure also has one of the strongest evidence bases of any ABA intervention. Decades of research across age groups, communication modalities, and target behaviors have consistently shown FCT to reduce interfering behavior while building functional communication skills. Recent meta-analyses confirm large effect sizes for both reducing challenging behavior and building replacement responses. FCT is among the most established interventions in the behavior analysis literature, and the behavior technicians who implement it daily can do so with high fidelity once trained on the procedure.
FCT is also flexible in how it can be delivered. Research has demonstrated effective implementation by behavior analysts, behavior technicians, classroom teachers, parents, and other caregivers—including delivery via telehealth. This breadth matters for families who can’t access in-person services regularly or who want to apply the procedure in home contexts. With appropriate coaching, parents implementing FCT at home have produced reductions in problem behavior comparable to clinic-based intervention.
FCT works best when it’s combined with other supportive procedures and documented as part of a broader plan. The communication response needs to be reinforced consistently across people and settings, prompts need to be faded systematically, and the team needs to plan for situations where the new response can’t be reinforced immediately. These details are typically captured in a written plan. For more, see our glossary entry on the behavior intervention plan.
FAQs About Functional Communication Training
How is FCT different from differential reinforcement of alternative behavior (DRA)?
FCT is technically a specific application of DRA, where the alternative behavior being reinforced is a communication response. DRA is the broader category—any procedure that reinforces a functionally equivalent alternative to an interfering behavior. FCT specifically uses communication (verbal, signed, picture exchange, AAC) as the alternative. Many behavior analysts treat the two terms as overlapping rather than distinct, with FCT being the most common form of DRA in practice.
Does FCT require a functional behavior assessment first?
In nearly all cases, yes. FCT only works if the communication response earns the same reinforcement that was maintaining the interfering behavior—which means the team has to know what was maintaining the behavior. A functional behavior assessment identifies the function, and that information drives the choice of communication response. Without it, the team might teach a communication response that doesn’t serve the same function, and the interfering behavior won’t decrease.
What if the learner can’t yet speak—can FCT still work?
Absolutely. FCT works with any communication modality. For learners who don’t yet speak, the team might teach signs, picture exchange (such as PECS), gestures, or use of a speech-generating device. Research has demonstrated FCT effectiveness across all these modalities. The behavior analyst selects the modality based on the learner’s current abilities, the speed at which the response can be learned, and the practical reality of where the communication will need to be understood.
How long does FCT take to work?
Timelines vary based on the learner, the complexity of the interfering behavior, and how consistently the team can implement the procedure. Some learners show meaningful reductions in interfering behavior within days; others need weeks or months of consistent practice. Research on parent-implemented FCT via telehealth has shown reductions in problem behavior averaging 93 to 98 percent over 12-week intervention periods, though individual results vary considerably. The behavior analyst monitors data weekly and adjusts the procedure if expected progress isn’t materializing.
Can FCT be used at home by parents?
Yes, and parent-implemented FCT has a strong research base. With appropriate coaching from a behavior analyst, parents have successfully implemented FCT at home for a wide range of interfering behaviors. The behavior analyst typically writes out the procedure, models it, coaches the parent on delivery, and supports troubleshooting as the family encounters real-world challenges. Many ABA programs include parent training as a core component specifically so that FCT and related procedures can carry over into home routines.
Key Takeaways About Functional Communication Training
- Functional Communication Training (FCT) is an ABA intervention that teaches a socially appropriate communication response to replace an interfering behavior that serves the same function.
- FCT was developed by Carr and Durand in the mid-1980s and is one of the most heavily researched interventions in behavior analysis.
- FCT depends on a functional behavior assessment to identify what’s maintaining the interfering behavior, so the new communication response can earn the same reinforcement.
- FCT can use any communication modality—spoken words, signs, picture exchange, AAC devices—depending on what fits the learner’s abilities and environment.
- Recent meta-analyses show FCT produces large effects for reducing challenging behavior and moderate-to-large effects for building replacement communication responses.
- FCT can be implemented by behavior technicians, behavior analysts, classroom teachers, and parents (including via telehealth), making it flexible across delivery contexts.
