4.3 Functional Communication Training (FCT) and Alternative Communication

Key Takeaways

  • Functional Communication Training (FCT) is a differential reinforcement procedure (DRA) that replaces problem behavior with a functionally equivalent communicative response.
  • To be effective, the communicative response must produce the exact same maintaining reinforcer identified during the Functional Behavior Assessment (FBA).
  • Initial FCT acquisition requires lower response effort than the problem behavior, immediate 1:1 reinforcement (CRF), and extinction for challenging behavior.
  • Augmentative and Alternative Communication (AAC) systems—ranging from low-tech PECS to high-tech speech-generating devices—provide accessible FCT modalities for non-verbal learners.
  • Schedule thinning in FCT must be systematically introduced using visual cues, wait timers, or multiple schedules (SD/S-Delta) to prevent constant requesting.
Last updated: July 2026

4.3 Functional Communication Training (FCT) and Alternative Communication

Exam Key Point: Functional Communication Training (FCT) is an evidence-based intervention that replaces problem behavior with an appropriate communicative response. FCT is technically a Differential Reinforcement of Alternative Behavior (DRA) procedure. The core rule of FCT is functional equivalence: the new communicative response must access the exact same reinforcer that previously maintained the problem behavior.

First developed by Carr and Durand (1985), FCT is based on the premise that many challenging behaviors (e.g., tantrums, self-injurious behavior, aggression, destruction) serve as non-verbal communication. When individuals lack effective verbal or alternative communication skills, problem behaviors emerge as the most efficient way to control their environment. FCT directly solves this deficit by establishing functional, socially acceptable communication.


Conceptual Foundations and Functional Equivalence

The cornerstone of successful FCT is functional equivalence. A replacement behavior is functionally equivalent only when it yields the identical reinforcer maintaining the problem behavior, as identified via a Functional Behavior Assessment (FBA).

Problem Behavior FunctionNon-Equivalent Replacement (INCORRECT)Functionally Equivalent Response (CORRECT)
Escape (Tantrum during math worksheet)Teaching client to say "I want break" when given a snack.Teaching client to hand a "Break Please" visual card or say "Break please" when given math.
Attention (Slapping therapist during paperwork)Giving client a sensory fidget spinner.Teaching client to tap therapist's arm and say "Play with me."
Tangible (Grabbing iPad from peer)Teaching client to ask for a hug.Teaching client to touch an "iPad" icon on a speech-generating device.
Automatic/Sensory (Body rocking due to under-stimulation)Verbal request for attention.Teaching client to turn on a sensory lamp or request a weighted blanket.

Selecting Augmentative and Alternative Communication (AAC) Modalities

Not all learners possess vocal speech. For non-verbal or minimally verbal individuals, FCT relies on Augmentative and Alternative Communication (AAC) systems. The BCBA/QBA selects the AAC modality based on the learner's motor skills, cognitive abilities, response effort, and environmental context.

1. Low-Tech AAC Systems

  • Picture Exchange Communication System (PECS): A structured 6-phase protocol where the learner picks up a physical picture icon, approaches a communicative partner, and hands over the icon to exchange for an item.
  • Communication Boards & Strips: Pointing to or touching picture symbols (Boardmaker icons, SymbolStix) fixed to a binder or wall board.
  • Icon Tapping / Card Hand-Over: Handing a single functional card (e.g., "Break" or "Help") to a teacher.

2. High-Tech AAC Systems

  • Speech-Generating Devices (SGDs): Electronic tablets or dedicated devices running specialized communication software (e.g., Proloquo2Go, TouchChat, LAMP Words for Life, Tobii Dynavox).
  • Operation: Learner taps a visual button on a screen, and the device vocally outputs synthesized speech (e.g., "I want water please").
  • Advantage: Highly legible to the general public; no training required for listeners to understand the request.

3. Manual Sign Language & Gestural Communication

  • Sign Language (ASL / Adapted Signs): Using motor signs (e.g., signing "More", "Eat", "All done").
  • Consideration: Requires the communicative partner to understand sign language; may require high fine-motor precision.

Step-by-Step Protocol for Implementing FCT

Implementing FCT requires rigid adherence to behavioral principles during initial acquisition:

[ Identify Function via FBA ] ---> [ Select Low-Effort FERB ] ---> [ Initial Acquisition: CRF (100%) + Extinction for Problem Behavior ] ---> [ Schedule Thinning & Tolerance Training ]

Step 1: Identify Function

Confirm the maintaining reinforcer via FBA (conducted under QBA/BCBA supervision).

Step 2: Select the Functionally Equivalent Replacement Behavior (FERB)

The replacement response must require lower response effort than the problem behavior. If screaming takes 2 seconds of effort, but finding a hidden communication book takes 30 seconds, the learner will continue screaming. The communicative response must be fast, easy, and reliable.

Step 3: Initial Acquisition on Continuous Reinforcement (CRF)

In the initial phase, deliver reinforcement on a Continuous Reinforcement (CRF) schedule (1:1 ratio):

  • Every single instance of the communicative response must result in immediate access to the maintaining reinforcer (0-2 second latency).
  • Use errorless learning (most-to-least physical prompting) to ensure rapid success without errors.

Step 4: Place Problem Behavior on Extinction

While the communicative response is reinforced 100% of the time, the problem behavior must be placed on extinction (zero access to the maintaining reinforcer when problem behavior occurs):

  • If the client screams for a break, do not provide a break.
  • Prompt the client physically to touch the "Break" card, then immediately grant the break.

Schedule Thinning and Tolerance Training in FCT

Once a learner acquires FCT on a CRF schedule, a new clinical challenge emerges: over-requesting. For example, a student taught to request a break may tap the "Break" card every 15 seconds, avoiding all academic instruction.

To address over-requesting, the BCBA/QBA will implement schedule thinning and tolerance training:

1. Visual Multiple Schedules ($S^D$ / $S^\Delta$ Cards)

  • $S^D$ Phase (Green Card Visible): Signals that communication is available. If the learner requests a break, it is granted immediately.
  • $S^\Delta$ Phase (Red Card Visible): Signals that communication is currently unavailable (e.g., during instructional work). Requests are acknowledged with a visual visual queue, and reinforcement is delayed until the Green card returns.
  • Systematic Thinning: Gradually increase Red Card time (e.g., 30s $\rightarrow$ 1min $\rightarrow$ 3min $\rightarrow$ 5min).

2. Delay-to-Reinforcement Fading

Introduce brief delays between the communicative response and reinforcer delivery:

  • Learner says "Break please." ABAT responds: "Great asking! Wait 5 seconds." (Build from 5s $\rightarrow$ 10s $\rightarrow$ 30s $\rightarrow$ 2min).

3. Teaching "No" and "Wait" Tolerance

Systematically teach the learner to accept denial or delay without problem behavior:

  • Present communicative opportunity $\rightarrow$ Learner asks $\rightarrow$ ABAT says "Not right now, wait" + hands token/visual timer $\rightarrow$ Reinforce calm waiting immediately with praise and secondary reinforcers.

Role of the ABAT in FCT Implementation

  1. Device Readiness: Ensure high-tech SGDs are fully charged, volume is adjusted, and target communication pages are open prior to session onset.
  2. Prompt Fading: Fade physical prompts quickly to gestural or positional prompts so the client initiates communication independently.
  3. Zero Reinforcement for Problem Behavior: Strictly maintain extinction for problem behaviors while ensuring immediate reinforcement for independent communication.
  4. Data Collection: Track independent communicative responses, prompted responses, and rate of target problem behaviors across sessions.
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Functional Communication Training (FCT) Implementation Flow
Test Your Knowledge

A client engages in property destruction specifically to escape difficult handwriting tasks. The ABAT is instructed to begin Functional Communication Training (FCT). Which replacement response demonstrates proper functional equivalence?

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D
Test Your Knowledge

During the initial acquisition phase of Functional Communication Training (FCT), what reinforcement schedule and prompting protocol should be utilized?

A
B
C
D
Test Your Knowledge

After acquiring FCT, a student begins tapping the 'Break' icon on their SGD every 10 seconds during class. How should the clinical team thin the FCT schedule appropriately?

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B
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D