Functional communication training, or FCT, is a behavioral intervention that teaches a person to use an appropriate communicative response in place of problem behavior such as aggression, self-injury, or tantrums. The approach was first described in 1985 by Edward Carr and V. Mark Durand, who showed that when children with developmental disabilities were taught to verbally request attention or help, their problem behaviors dropped substantially and reliably across participants.1PubMed Central. Reducing behavior problems through functional communication training Since then, FCT has become one of the most widely studied function-based interventions in applied behavior analysis, and recent meta-analytic evidence puts it squarely in the category of evidence-based practice for reducing challenging behavior in young children with autism.
How FCT Works
The logic behind FCT rests on a simple but powerful observation: problem behaviors usually serve a purpose. A child who bites might be trying to escape a difficult task. A teenager who screams might be seeking attention. An adult who throws objects might want access to a preferred item. These behaviors “work” in the sense that they produce a specific outcome from the environment. FCT replaces the problem behavior with a communication response that gets the same outcome more efficiently and more acceptably.
The process has two essential steps. First, you figure out what the problem behavior is actually achieving for the person. Second, you teach a new communicative response that produces that same reinforcer, while simultaneously ensuring the problem behavior no longer works. If a child’s aggression is maintained by escape from homework, FCT would teach the child to request a break using words, a picture card, or a gesture. Asking for a break now produces relief; hitting does not.
Why Functional Assessment Comes First
The entire intervention hinges on correctly identifying the function of the problem behavior before treatment begins. If you guess wrong about why the behavior is happening and teach a communication response tied to the wrong reinforcer, you are unlikely to see much improvement. A review of the FCT literature found that the large majority of published studies used formal functional analysis, in which potential controlling variables are systematically tested, to identify what maintains the problem behavior before FCT is introduced.2PubMed Central. Functional Communication Training: A Review and Practical Guide Without accurate identification of the maintaining reinforcer, the event assigned to follow the new communicative response may be functionally unrelated to the problem behavior, making the intervention less likely to work.
In practice, a functional assessment might reveal that a child’s tantrums happen almost exclusively when adult attention is low and task demands are high. That assessment data then guides which communication responses to teach. In the original 1985 study, the assessment showed that low attention and high task difficulty were discriminative for misbehavior, and the children were taught to solicit attention or assistance verbally based on those specific findings.3PubMed Central. Reducing behavior problems through functional communication training Getting this step right is what separates FCT from a generic “teach the child to use their words” approach.
How Effective Is FCT at Reducing Problem Behavior
The evidence base is strong. A meta-analysis of 34 single-case design studies examining FCT in young children with autism found large effects for reducing challenging behavior and moderate-to-large effects for increasing the replacement communication response.4PubMed Central. A Meta-Analysis of Functional Communication Training for Young Children with ASD and Challenging Behavior in Natural Settings A broader mega-review that aggregated six systematic reviews and meta-analyses of FCT in educational settings also found consistent positive effects on challenging behavior reduction.5Journal of Behavioral Education. A Mega-Review of Functional Communication Training for Students with Disabilities in Educational Settings
That said, the research also flags that FCT works much better when it includes extinction of the problem behavior. A review of published applications found that FCT without extinction failed to reduce problem behavior below 90% of baseline levels in any of 11 cases where it was tried alone. By contrast, FCT with extinction produced reductions of 90% or more in roughly half of 25 applications.6PubMed Central. Functional Communication Training: A Review and Practical Guide Extinction here means the problem behavior simply stops producing its usual payoff. Teaching a child to ask for a break only works well if hitting no longer also produces a break.
Choosing the Communication Response
FCT does not require spoken language. The replacement response can take many forms: vocal speech, picture exchange systems like PECS, manual signs, pointing to icons on a communication board, or pressing a button on a speech-generating device. The choice depends on the person’s existing skills, their physical abilities, and the practical realities of the setting they are in.
There is some evidence that the modality matters for specific outcomes. A study comparing manual signs and PECS in children with autism found that children using PECS reached the goal of making 20 spontaneous requests more quickly, while children using signs made the transition from augmentative communication to spontaneous vocal requests faster.7PubMed Central. AAC and Autism: Manual Signs and Pecs, a Comparison Neither system was universally superior. The practical takeaway is that the “best” modality depends on the individual child and the goals of treatment.
One important practical consideration is whether communication partners in the person’s daily life will recognize and respond to the chosen response. A child who learns to hand over a picture card at a clinic needs caregivers, teachers, and peers who will honor that card in the classroom, at home, and on the playground. If the response is too effortful or unfamiliar to the people who will encounter it, it may go unreinforced in natural settings, and the old problem behavior may return.
The Schedule Thinning Problem
Here is where FCT gets tricky in real life. Early in treatment, every appropriate communication response is reinforced immediately. If a child hands over a “break” card, they get a break right away. This rich schedule of reinforcement is necessary to build the new behavior and outcompete the old one. But it is not sustainable. A teacher cannot honor a break request every 30 seconds for an entire school day. A parent cannot drop everything each time their child presses a button.
Schedule thinning is the process of gradually increasing the delay between the communication response and the delivery of the reinforcer. In one study, delays were stretched from 5 seconds up to 4 or 5 minutes across eight or nine steps, with each step requiring two consecutive sessions of low problem behavior before advancing.8PubMed Central. Schedule Thinning Following Communication Training: Using Competing Stimuli To Enhance Tolerance To Decrements In Reinforcer Density Both chained schedules and multiple schedules have been shown to reduce problem behavior during thinning, with some evidence that chained schedules produce higher compliance in certain individuals.9PubMed. Schedule Thinning Following Functional Communication Training: Effects of Chained and Multiple Schedules
A common approach uses multiple schedules, where signals indicate to the person whether reinforcement is currently available. A green card might signal “you can ask for a break and get one” while a red card signals “breaks are not available right now.” A more recent innovation, the probabilistic delay-tolerance approach, has emerged because traditional delay schedules frequently trigger a return of problem behavior during the thinning process.10PubMed Central. Updated Recommendations for Reinforcement Schedule Thinning following Functional Communication Training Getting schedule thinning wrong is one of the most common ways FCT falls apart after initial success.
When Problem Behavior Comes Back
Resurgence is the technical term for the reappearance of a previously reduced behavior when conditions change, and it is a genuine concern with FCT. Research has shown robust recovery of problem behavior during resurgence tests, sometimes above original baseline rates.11PubMed Central. An Evaluation of Resurgence During Treatment with Functional Communication Training If reinforcement for the communication response is withheld briefly or thinned too quickly, the old problem behavior can come roaring back, even when that behavior is still technically on extinction.
A large-scale analysis of 239 thinning steps across clients in an intensive day treatment program found that resurgence occurred in about 41% of thinning steps. When it did occur, the rate of problem behavior in the first session after the thinning step was roughly seven times higher than the average of the five sessions before that step.12PubMed. Prevalence of resurgence during thinning of multiple schedules of reinforcement following functional communication training That is a meaningful spike, and it highlights why schedule thinning needs to be done carefully and with a clear plan for what to do if the person’s behavior deteriorates.
There are strategies to reduce resurgence. One study found that when a signal indicating reinforcement was unavailable remained continuously visible during an extinction challenge, destructive behavior stayed near zero, whereas traditional FCT without that signal produced resurgence.13PubMed Central. A Preliminary Investigation on Improving Functional Communication Training by Mitigating Resurgence of Destructive Behavior Another approach involves limiting the person’s early exposure to the conditions that trigger problem behavior when FCT is first introduced, which can prevent or reduce extinction bursts. One study found that the limited-exposure condition rapidly reduced destructive behavior during every application, while the extended-exposure condition produced extinction bursts in five of six applications.14PubMed Central. Further evaluation of differential exposure to establishing operations during functional communication training
Long-Term Maintenance
One of the most encouraging aspects of the FCT literature is evidence that the effects can last. A study following three students after FCT found that reductions in challenging behavior transferred across new tasks, environments, and teachers, and were generally maintained 18 to 24 months after the intervention was introduced.15PubMed Central. Functional communication training to reduce challenging behavior: maintenance and application in new settings A longer-term analysis of FCT conducted in young children’s home settings similarly concluded that the intervention produces reliable long-term effects when treatment is sustained over time.16PubMed Central. The Long-Term Effects of Functional Communication Training Conducted in Young Children’s Home Settings
However, durability depends on conditions. A study comparing FCT to time-out found that durable results were achieved only in the group that received FCT across different stimulus conditions. Children whose challenging behaviors had been reduced using time-out resumed those behaviors in the presence of new teachers who were unfamiliar with the child’s intervention history.17PubMed Central. An analysis of maintenance following functional communication training This suggests that teaching a communicative replacement rather than simply suppressing the behavior gives the person a portable skill that works even when the environment changes. The communication response travels with the person in a way that external contingency management does not.
Parents as Implementers
Clinic-based FCT is effective but limited if it never transfers to the home, the grocery store, or the car. Increasingly, researchers and clinicians have focused on training parents and other caregivers to implement FCT themselves. A study of parent coaching found that verbal and written instructions combined with performance feedback led to accurate parent implementation of FCT during trained routines, though some parents needed additional training to generalize the procedures to new routines.18Topics in Early Childhood Special Education. Teaching Parents to Implement Functional Communication Training for Young Children With Developmental Delays A systematic review of parent-implemented FCT for nonvocal children with autism and intellectual disabilities found high procedural fidelity and social validity across studies, with about half incorporating cultural adaptations to fit diverse families.19Education and Training in Autism and Developmental Disabilities. Parent-Implemented Functional Communication Training to Reduce Challenging Behavior in Nonvocal Children With ASD and IDD From Diverse Families: A Systematic Review
Telehealth has expanded this reach dramatically. A randomized controlled trial found that parent-implemented FCT delivered via telehealth coaching achieved a mean reduction in problem behavior of 98% over 12 weeks, compared to limited improvement in children receiving treatment as usual.20PubMed Central. A Randomized Controlled Trial of Functional Communication Training via Telehealth for Young Children with Autism Spectrum Disorder An earlier study using a similar telehealth model reported an average reduction of about 94% in problem behavior when parents conducted FCT with remote consultation from experienced behavior analysts.21PubMed Central. Conducting Functional Communication Training via Telehealth to Reduce the Problem Behavior of Young Children with Autism Telehealth delivery has also been tested with school personnel as implementers, with initial results supporting its validity as a remote service model.22PubMed Central. Effectiveness of a Brief Functional Analysis and Functional Communication Training Conducted Through Telehealth
FCT in Schools and Early Childhood Settings
Schools present unique challenges for FCT. Classrooms are busy, teachers have many students, and the kind of one-on-one attention FCT often requires in its early stages can be hard to arrange. Despite this, a systematic review of FCT in early care and education settings found strong effects for reducing challenging behavior, although the authors noted that more studies with rigorous methodology are needed before FCT meets the What Works Clearinghouse’s formal criteria for evidence-based practice in those specific settings.23Education and Training in Autism and Developmental Disabilities. Systematic Review of Functional Communication Training in Early Care and Education Settings Trial-based functional analyses, which embed brief assessment probes into the natural classroom routine rather than requiring a separate testing room, have been shown to successfully identify behavioral functions and lead to effective FCT in early childhood settings.24PubMed Central. Trial-based functional analysis and functional communication training in an early childhood setting
The mega-review of educational settings noted variability in outcomes based on moderators like the specific setting, the communication modality used, and who implemented the intervention.25Journal of Behavioral Education. A Mega-Review of Functional Communication Training for Students with Disabilities in Educational Settings This variability is not surprising given the range of classrooms, ages, disability profiles, and staffing configurations involved. It points to the importance of adapting FCT procedures to the realities of each environment rather than applying a rigid protocol.
Practical Functional Assessment and Skill-Based Treatment
A newer framework called the Practical Functional Assessment and Skill-Based Treatment, or PFA/SBT, builds on the principles of FCT while reorganizing the assessment and treatment process. PFA/SBT uses open-ended interview and direct observation to develop an understanding of the conditions under which challenging behavior occurs, then moves into a treatment that teaches multiple skills in a structured sequence, including functional communication, toleration of delays, and cooperation with transitions. One study implemented this approach with six children with autism in a specialized school and found that challenging behavior was reduced to near-zero levels across multiple staff and settings, with follow-up data showing effects that persisted one year after treatment ended and the elimination of physical restraint use for all participants.26PubMed. Long-term effectiveness and generality of practical functional assessment and skill-based treatment
The PFA/SBT model has also shown promise with individuals who have co-occurring autism and mental health disorders, with problem behavior remaining low after reinforcement was thinned by increasing a requirement of completing difficult tasks.27Behavioral Interventions. Generality of the practical functional assessment and skill‐based treatment among individuals with autism and mental health disorders A pilot investigation demonstrated that parents with limited prior knowledge of behavioral principles could be coached to implement PFA/SBT procedures via telehealth safely and with high fidelity, and that dangerous forms of challenging behavior rarely occurred during the treatment period.28Clinical Case Studies. Evaluating Practical Functional Assessment and Skill-Based Treatment for Severe Challenging Behavior via Telehealth with Novice Dual Parent Implementers: A Pilot Investigation PFA/SBT does not replace FCT so much as embed it within a broader skill-building framework, addressing some of the challenges around schedule thinning and resurgence that have been identified in the traditional FCT literature.
Common Misconceptions About FCT
One widespread misunderstanding is that FCT simply means “teaching a child to use words instead of hitting.” The communication piece is only half the intervention. Without the functional assessment identifying the specific reinforcer maintaining the problem behavior, and without rearranging the environment so the old behavior no longer pays off, teaching communication alone is unlikely to produce lasting change. The replacement response has to access the same reinforcer the problem behavior was getting. Teaching a child to say “please” when their aggression was actually about escaping demands will not help.
Another misconception is that FCT is only for young children with autism. While most of the published research involves children with developmental disabilities, the underlying principles apply to anyone whose problem behavior serves a communicative function. Discriminative stimulus control procedures have been used to reduce destructive behavior regardless of whether the functional reinforcer or an alternative reinforcer was available.29PubMed Central. Establishing discriminative control of responding using functional and alternative reinforcers during functional communication training The approach has also been explored with individuals who have acquired brain injuries, though the evidence base for adult and acquired populations is thinner and less conclusive than it is for children with developmental disabilities.
A third misconception is that once FCT works, you can stop and the results will hold forever without any environmental support. The maintenance literature suggests otherwise. Results travel well when the person has been taught a truly functional communicative response that works across different people and settings, but if new environments fail to reinforce the communication response, or if the old problem behavior starts getting reinforced again by caregivers who have not been trained, problem behavior can return.30PubMed Central. An analysis of maintenance following functional communication training The communication response needs an audience that will respond to it. Planning for that audience, whether through caregiver training, school communication plans, or transition documents, is part of making FCT stick.