TL;DR: Functional Communication Training teaches a learner to use an efficient, socially acceptable communicative behavior that accesses the same reinforcement as their problem behavior. When FCT is built on a solid FBA, implemented with extinction, and faded systematically, it produces durable reductions in challenging behavior. When any of those elements are missing, it fails — sometimes dramatically.
Functional Communication Training (FCT) was introduced by Carr and Durand in 1985 and remains one of the most evidence-based interventions in the behavior analyst’s toolkit. The core idea is elegant: if a behavior is occurring because it works — because it gets the person what they need — then teach a better behavior that gets them the same thing. Replace the problem behavior with a functional communicative equivalent.
That logic is sound. The execution is where things get complicated.
Why FCT Works — and Why It Fails Without All Its Parts
FCT is not just “teach the learner to ask for a break instead of throwing materials.” That framing leaves out the most critical component: extinction.
FCT only produces behavior change when the replacement communication response (FCR) is more efficient than the problem behavior — meaning it produces the reinforcer faster, with less effort, and more reliably. For the FCR to become efficient, the problem behavior must stop working. That means implementing extinction simultaneously: the function-maintaining consequence no longer follows the problem behavior.
Without extinction, the learner has two routes to the reinforcer instead of one. They will use whichever works faster in the moment. If problem behavior has a long history and the FCR is new and fragile, problem behavior will usually win.
Three conditions must be true for FCT to work:
- The FBA correctly identified the function. If the intervention is designed for escape but the function is attention, the FCR will not contact the maintaining reinforcer. Nothing sticks.
- Extinction is in place for the problem behavior. Reinforcing the FCR while also reinforcing problem behavior is not FCT — it is differential reinforcement of alternative behavior (DRA) without extinction, which can reduce but rarely eliminates the target.
- The FCR is genuinely easier to perform than the problem behavior. If the FCR requires more effort, time, or precision than the challenging behavior, the learner will default to what has always worked.
How to Implement FCT: The Four Core Steps
Step 1 — Identify the Function (and Confirm It)
FCT begins with a completed Functional Behavior Assessment. Ideally, this includes indirect assessment (interviews, rating scales such as the MAS or QABF), direct observation (ABC data), and — when indicated — a functional analysis (FA) to confirm the function experimentally. Running FCT on interview data alone carries real risk. When a problem behavior is severe, an FA-confirmed function is worth the additional time investment.
Step 2 — Select and Teach the FCR
Choose a communicative response that:
- Produces the same class of reinforcement. Escape-maintained behavior → request a break or help. Attention-maintained behavior → request attention. Tangible → request the item. Automatic reinforcement → more complex; consider whether the behavior can be redirected to a less disruptive form.
- Is within the learner’s current response capabilities. A learner without functional speech can use a PECS card, an AAC device, or a simple gesture. The FCR does not need to be verbal — it needs to be functional.
- Is contextually salient and easy to prompt. The FCR should be easy to emit in the conditions where problem behavior occurs, easy to prompt in the moment, and easy to reinforce immediately.
Teach the FCR in structured practice first if necessary. Use prompting and prompt fading (most-to-least or least-to-most depending on the learner’s prompt history) to establish the response in low-demand, high-motivation contexts where the function is likely active.
Step 3 — Implement Extinction for the Problem Behavior
This is the hardest step for most teams. Extinction means the problem behavior no longer contacts its reinforcer — and extinction produces an extinction burst before it produces reduction. Prepare the team: initial increases in the rate, intensity, or variability of problem behavior are a normal sign that extinction is working, not a sign that FCT is wrong.
Document the extinction procedure explicitly in the BIP. Name the function-maintaining consequence and describe exactly what staff should do instead. If team response is inconsistent — some staff implement extinction, others do not — the schedule becomes intermittent, the behavior becomes more persistent, and FCT stalls. Consistency here is not a preference; it is a clinical requirement.
Step 4 — Thin the FCR Schedule
Once the FCR is stable and problem behavior has reduced, begin thinning the reinforcement schedule for the FCR. This step is often skipped, and it’s a mistake. A dense CRF schedule that works in clinic rarely transfers to natural environments where the reinforcer is not always immediately available.
Thin gradually: move from CRF to FR2 to FR3, or from immediate reinforcement to brief delays. Monitor for resurgence of problem behavior as an indicator that you are thinning too fast. The goal is a learner who can tolerate realistic delays and densities of reinforcement — not a learner who only uses the FCR when the outcome is guaranteed to be immediate.
The Four Most Common FCT Mistakes
1. Treating the FCR as the whole intervention. FCT is a package — FCR plus extinction. The FCR without extinction is incomplete and often insufficient. Document and implement both from the start.
2. Choosing an FCR the learner cannot yet reliably emit. If the FCR requires a skill the learner hasn’t established, teach that skill first or choose a simpler form. An FCR the learner can’t consistently produce under low-demand conditions will not hold up under the conditions that occasion problem behavior.
3. Skipping schedule thinning. A learner who can only tolerate waiting for reinforcement when they are immediately accommodated will struggle in every natural environment. Tolerance training is part of FCT, not an optional add-on.
4. Running FCT without team-wide fidelity. Extinction is only effective when it’s implemented consistently across all staff, all settings, and all times of day. Run Behavior Skills Training (BST) with the full team before going live — modeling, rehearsal, and feedback, not just a training video. A single inconsistent team member can maintain an intermittent reinforcement history that keeps problem behavior alive for months.
How Kipr Helps
FCT is technically straightforward to describe and genuinely difficult to execute. The hard part is not knowing the steps — it’s staying composed and consistent when the learner escalates during an extinction burst, when the team member across the room is uncertain, when the FCR isn’t prompting cleanly, and when the clinical judgment call has to happen in real time.
That’s a situation that benefits from reps. Kipr’s simulation environment lets BCBAs and behavior therapists practice FCT scenarios before doing any of it with a real client — running extinction through a difficult escalation, prompting and fading the FCR under pressure, and making the judgment call about schedule thinning timing. The decision-making skills that make FCT effective don’t come from reading the procedure. They come from rehearsing it until the response is fluent.
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