Functional Communication Training

Teaching the replacement that does the work the problem behavior was doing

Why this brief

Functional Communication Training (FCT) — first formalized by Carr and Durand in the mid-1980s and now one of the most evidence-supported behavior interventions in special education — turns problem behavior into communication. The core idea: behavior that's serving a function (escape, attention, tangible, sensory) doesn't go away by being suppressed. It goes away when the student has a more effective way to meet the same need. The work is to teach that more effective way.

This brief covers what FCT is, how it gets designed, what the para's role looks like in implementation, the common ways it goes wrong, and what to do when the replacement isn't sticking. It assumes function-based thinking (cross-ref 05.01) — without that lens, FCT can be misapplied.

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| This is not just an autism interventionFCT was originally developed in autism research and is heavily used there, but it applies to any student whose problem behavior has a communicative function — which is most students. The procedure looks different for a 5-year-old non-speaking student learning to hand a card and a 16-year-old verbally fluent student learning to ask for a break with a script. The principles are the same. |

1\. What FCT is

FCT is a teaching procedure with three components:

Identify the function of a problem behavior (typically through FBA — cross-ref 05.02).

Teach the student a replacement communication response that meets the same function.

Reinforce the replacement response richly while reducing the reinforcement available for the problem behavior.

The replacement might be a spoken phrase, a sign, an icon on a communication device, a card the student hands to an adult, an AAC selection, a gesture, a written request. What matters is that it produces the same outcome the problem behavior was producing — and that the student can perform it under the conditions where the problem behavior happens.

1.1 An everyday example

A 4th-grade student with autism throws materials when math gets hard. The team's FBA identifies the function as escape from non-preferred work. The team designs FCT: teach the student to hand a "break" card to the adult, which produces a 2-minute break from math. Early in teaching, every time the student hands the card, they get the break. Throwing materials is responded to calmly with the demand maintained. Over time, the student uses the card consistently; the throwing decreases.

2\. Why FCT works

Several converging reasons:

It addresses the function. The student's underlying need (in the example above, the need for a break from hard work) is real and isn't going away. FCT meets it through a different channel.

It's faster than extinction alone. Trying to extinguish problem behavior without teaching a replacement often produces extinction bursts, response covariation (the student tries a different problem behavior with the same function), and slow change.

It teaches a generalizable skill. Communication is itself a skill the student carries forward.

It improves quality of life. Students who can communicate their needs through accepted channels have more dignity, more autonomy, and more access to environments than students who can't.

It's well-evidenced. Decades of research support the basic procedure across populations and settings.

3\. How an FCT plan gets designed

Designing FCT is typically the BCBA's, special education teacher's, or SLP's work — paras don't design FCT plans, but they do implement them, and understanding the design helps with fidelity. Key design decisions:

3.1 Function identification

From the FBA. The replacement must match the function. A break card for a student whose function is escape; a help card for a student whose function is attention or assistance; an icon for a desired item for a student whose function is tangible; a sensory tool for a student whose function is sensory.

3.2 Replacement form

What can the student actually do? Form depends on motor skills, current communication level, AAC system if any. Common forms:

Picture exchange — student hands an icon or card to an adult.

AAC button or icon selection.

Sign — manual sign for break, help, more, etc.

Spoken phrase — "break, please" or a script.

Written request — older students.

Gesture — pointing, eye-gaze.

3.3 Effort

The replacement should be at least as easy as the problem behavior. If a student can throw a chair effortlessly but the replacement requires walking across the room to hand a card to a specific adult, the effort mismatch favors the chair. Make the replacement low-effort, especially early.

3.4 Recognizability

Adults need to recognize the replacement. "He sometimes touches his ear when he wants a break" doesn't work if half the staff don't know. The replacement must be obvious enough that any adult on the team responds to it.

3.5 Reinforcement schedule

Initially, the replacement is reinforced every single time. Continuous reinforcement during acquisition is well-evidenced. Over time, the schedule is thinned — but only after the replacement is reliable.

3.6 Schedule of access

If the student is asking for a break ten times an hour with the new card, and the team grants every break, instructional time disappears. The plan typically includes a schedule of access — perhaps initially every request honored, later moving to cards-redeemable-for-breaks-at-set-times, eventually self-managed regulation. The fade is part of the plan.

4\. Implementation — what the para does

4.1 Set up the environment

Replacement is visible and accessible at all times in the moments where it's needed.

Adults are positioned to notice and respond quickly.

Other paras and staff know the system and respond consistently.

The student has had the replacement modeled multiple times before being expected to use it.

4.2 In the moment

Watch for early signs of the function activating — the trigger context, the body cues, the early agitation (cross-ref 05.10).

Prompt the replacement before the problem behavior occurs. Early in teaching, you often physically prompt the student through the replacement.

Reinforce immediately when the replacement happens — even if it was prompted.

If the problem behavior happens anyway, respond per the BIP — typically calmly, without granting the function (don't deliver the break for the tantrum), while keeping the replacement available.

Document — both replacement use and problem behavior occurrence.

4.3 Prompting and fading

Initially, the replacement is heavily prompted (cross-ref 04.02 on prompting hierarchies; 04.03 on fading). The fade across trials looks like:

Trial 1: Adult physically prompts the student through the replacement at the trigger moment.

Trial 2-5: Adult prompts more lightly (model, gesture, verbal).

Trial 6-10: Adult delivers a brief delay before prompting; student begins to initiate.

Subsequent trials: Adult fades back; student initiates independently.

Fading is not skipping; it's stepping down systematically. A student who used to need physical prompting and now uses the replacement independently is the goal.

5\. The early days of an FCT program

The first few weeks of FCT often look messy. Several patterns are normal and don't mean the plan is failing:

Replacement use spikes — sometimes dramatically. The student has just been given an effective tool; expect them to use it more than expected.

Problem behavior may persist alongside the replacement before declining. Both can coexist for a stretch.

Extinction bursts can happen — brief intensification of the problem behavior before it declines.

Some students try variants — using the replacement in new contexts, or in ways the team didn't predict.

Team consistency wobbles — different staff respond differently in the first weeks while everyone learns the system.

These patterns are usually managed by holding to the plan with high fidelity for several weeks. Premature changes ("the replacement isn't working — let's try something else") often abandon FCT before it's had a chance to stabilize. The BCBA or supervising teacher should be looking at trend data over weeks, not days.

6\. Thinning the schedule

Once the replacement is reliable, the team begins thinning — making the replacement less effortful for the team and more sustainable in the classroom. Thinning has to be planned. Without it, students can be in continuous reinforcement mode forever, which isn't viable in real classroom settings.

6.1 Common thinning approaches

Multiple-schedule thinning — a visual signal indicates when the replacement is honored vs. when it's delayed. The student learns to wait when the signal is off.

Delay-to-reinforcement — the replacement is honored, but with progressively longer delays.

Demand fading combined with FCT — gradually increasing the work demand while maintaining the replacement availability.

Token systems — the replacement earns tokens that redeem for the function periodically.

6.2 Watch for reverse drift

Sometimes thinning is too aggressive and the student starts using the problem behavior again. The fix is usually to back up to the previous step, stabilize, then try thinning more gradually. The data tells you when you've moved too fast.

7\. Generalization

FCT replacements often work in the setting where they're taught and not in others. A student who reliably uses a break card with one para in one room may not use it with a substitute or in a different room or with a different staff member. Generalization is part of plan design — programmed, not assumed.

7.1 Programming for generalization

Multiple instructors deliver the program from the start when possible.

Multiple settings are introduced deliberately.

Multiple variations of the trigger context.

Multiple forms of the replacement where appropriate (spoken phrase + AAC + sign).

Generalization probes scheduled in different conditions to monitor.

7.2 When generalization fails

If the replacement works in one context only, it's not yet learned. The team may need to actively teach in additional contexts before the student fully owns the skill.

8\. Common problems and what to do about them

| Problem | Likely cause / what to try |

| :-: | :-: |

| Student uses the replacement constantly, blocking instruction. | Replacement is doing its job. Plan for thinning the reinforcement schedule. Don't punish the use; fade it gradually. |

| Student doesn't use the replacement; problem behavior continues. | Replacement may be too effortful, not recognized by all staff, not reinforced reliably, or not yet taught to mastery. Check fidelity, calibration, and prompt level. |

| Replacement works with one staff and not others. | Calibration. The replacement needs consistent response across the team. |

| Replacement works in one setting only. | Generalization. Plan for cross-setting teaching. |

| Student uses the replacement in inappropriate contexts (asking for break during specials, asking for attention during testing). | Some student-initiated generalization; sometimes appropriate, sometimes needs schedule-of-access boundaries. Consult BCBA or supervising teacher. |

| Problem behavior shifts to a new form (response covariation). | The function is still active and the replacement isn't fully meeting it. Reassessment may be needed. |

| Student stops using the replacement after weeks of success. | Reinforcement may have thinned too aggressively, or the function may be different now. Back up the schedule; reassess. |

| The team isn't running the plan with fidelity. | The most common reason FCT fails. Calibration meeting; programming sheets; direct observation. |

9\. Beyond basic FCT

FCT extends beyond simple break-asking and help-asking in ways the para may encounter:

Tolerance training — teaching students to wait when the replacement can't be honored immediately.

Choice-making — replacement that involves selecting between options rather than a single response.

Self-management — replacement that the student uses to monitor their own state and request what they need.

Multi-step communication — replacement that includes multiple components ("I'm feeling overwhelmed; can I take a break and come back in 5 minutes?").

Functional communication for students with complex communication needs — robust AAC programming integrated with FCT.

These extensions are typically designed by the SLP, BCBA, or special education teacher; the para implements.

10\. When FCT isn't enough

FCT is powerful but not universal. Some situations where FCT alone isn't sufficient:

Setting events overwhelm the system. A student dealing with home-front trauma, missed sleep, hunger, or pain has a smaller window for any replacement to succeed.

Skill deficits make the replacement harder than the problem behavior.

The function is more complex than the FBA captured (multiply-maintained behavior).

The team isn't running the plan with fidelity.

The reinforcement isn't reinforcing — what the team thought was the function isn't quite what's maintaining the behavior.

FCT is a piece of the system, not the whole system. Antecedent strategies (cross-ref 05.04), trauma-informed practice (cross-ref 05.14), self-regulation instruction, sensory supports, instructional fit, and family/medical coordination all matter alongside.

11\. Ethical considerations

11.1 Don't suppress communication

Some legacy approaches treated student attempts to communicate (challenging behaviors, stimming, vocalizations) as things to extinguish without teaching alternatives. This is not FCT. FCT explicitly teaches communication; suppression without replacement is a different and increasingly rejected practice.

11.2 Honor refusals

If a student uses the replacement to ask for a break, give the break. Honoring the replacement is the contract. "You asked, but I'm not going to give it to you" undermines the entire system. (Schedule-of-access nuances are handled by the BCBA in design; in the moment, when the system says yes, the answer is yes.)

11.3 Don't make replacements contingent on "good behavior"

"You can use your break card if you've been doing your work" turns the replacement into a reward for compliance and breaks the function-based logic. The replacement is for whenever the function is active.

11.4 Coordinate with the AAC team

If the student uses AAC, the replacement is part of their communication system. The SLP needs to be in the design conversation. AAC users do not have FCT bolted onto them; FCT extends their existing communication tools.

12\. Common pitfalls

Skipping the FBA. FCT without function identification is just "teach a skill" — sometimes useful, often misaimed.

Treating the replacement as advisory. If the student uses the replacement, the team must respond.

Reinforcing the problem behavior accidentally — talking the student through it, giving big reactions, eventually relenting.

Different paras using different replacements, signals, or response patterns.

Teaching the replacement only when the student is calm, not in the trigger context where they actually need it.

Premature thinning.

Premature abandonment when the early weeks are bumpy.

Letting the replacement be more effortful than the problem behavior.

Not programming for generalization.

Treating FCT as a single intervention rather than as part of a behavior plan that also includes antecedent strategies and instructional supports.

13\. Resources

Foundational and current research

Carr & Durand (1985) — Reducing behavior problems through functional communication training — JABA — Foundational paper.

Tiger, Hanley, Bruzek (2008) — Functional Communication Training: A review and practical guide — Behavior Analysis in Practice — Practitioner-focused review.

AFIRM — Functional Communication Training module — afirm.fpg.unc.edu — Free self-paced module with implementation checklist.

National Clearinghouse on Autism Evidence and Practice (NCAEP) — ncaep.fpg.unc.edu — FCT is among the 28 EBPs.

Practice resources

PrAACtical AAC — Functional Communication — praacticalaac.org

Cooper, Heron & Heward — Applied Behavior Analysis — Pearson — Standard reference for FCT design.

Cross-references

Brief 05.01 — Function-Based Thinking — this library

Brief 05.02 — Functional Behavior Assessment — this library

Brief 05.03 — Reading and Running a BIP — this library

Brief 05.04 — Antecedent Strategies — this library

Brief 04.02 — Prompting Hierarchies — this library

Brief 04.03 — Prompt Fading — this library

Brief 10.02 — AAC Overview — this library

Brief 12.06 — Working with the BCBA — this library

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