6.1 Function-Based Extinction and Replacement Behavior Selection

Function-Based Extinction and Replacement Behavior Selection

In applied behavior analysis and Qualified Behavior Analyst (QBA) practice, behavior reduction must never occur in a vacuum. Under the core ethical standards of the QABA credentialing board, reducing an unwanted or challenging behavior requires a dual-focused strategy: systematically eliminating the reinforcing consequences maintaining the behavior (function-based extinction) while simultaneously teaching and reinforcing an appropriate functionally equivalent replacement behavior (FERB).

---

1. Matching Extinction to Behavioral Function

Extinction is defined as a procedure in which reinforcement for a previously reinforced behavior is discontinued, resulting in a decrease in the future frequency of that behavior. A common clinical error is applying a generic extinction procedure—such as planned ignoring—to behaviors regardless of their maintaining function. To be effective and ethical, extinction must be matched specifically to the functional reinforcer identified during a Functional Behavior Assessment (FBA).

Function-Specific Protocols

1. Attention Extinction (Planned Ignoring): When self-injurious behavior or disruptive vocalizations are maintained by staff or caregiver attention, clinicians must ensure zero contingent social delivery. Even brief eye contact, verbal reprimands ("Don't do that"), or facial expressions function as positive reinforcers and will maintain the target behavior.
2. Escape Extinction (Three-Step Prompting / Non-Removal of Demands): If aggression occurs to escape academic or vocational tasks, staff must maintain the demand using a least-to-most prompting hierarchy (e.g., Gestural → Verbal → Full Physical Guidance) until the task step is completed. Removing the task contingent on problem behavior inadvertently reinforces the behavior via negative reinforcement.
3. Tangible Extinction: If tantrums occur when a tablet is removed, staff must strictly withhold the tablet during and after the tantrum. The item is only restored during non-problem periods or following an appropriate mand.
4. Automatic / Sensory Extinction: Because automatic reinforcement occurs without social mediation, extinction requires altering the physical consequences. For example, placing carpet over hard flooring eliminates the auditory feedback of floor-slapping. When total sensory extinction is impossible, response blocking is implemented to interrupt the response before sensory feedback occurs.

---

2. Selection Criteria for Replacement Behaviors (FERBs)

Selecting an appropriate replacement behavior is not merely choosing a desirable behavior; it is an engineering task governed by behavioral principles. A replacement behavior will fail if it does not match the target behavior's function or if it demands excessive effort from the learner.

       [ Target Problem Behavior ]
                   │
                   ▼ (Identified Function: e.g., Escape from Demand)
                   │
    ┌──────────────┴──────────────┐
    │                             │
    ▼                             ▼
[ Non-Equivalent Response ]   [ Functionally Equivalent (FERB) ]
(e.g., Sitting quietly)       (e.g., Requesting a 2-minute break)
    │                             │
    ❌ Fails to reduce escape-     ✅ Replaces problem behavior with
       maintained behavior           equal/superior reinforcement efficiency

The Response Efficiency Rule

According to the Response Efficiency Rule, a learner will engage in whichever behavior yields the highest rate of reinforcement with the lowest physical and cognitive effort. When selecting a FERB, QBAs must evaluate four critical dimensions of response efficiency:

1. Functional Equivalence: The replacement behavior MUST produce the exact same reinforcer (e.g., escape, attention, tangible item) as the problem behavior. Teaching a client to ask for a toy when their self-injury is maintained by escape from math tasks will not reduce self-injury.
2. Physical Response Effort: The replacement response must require equal or less physical effort than the problem behavior. If hitting requires minimal physical effort, asking a learner to construct a complex 5-word sentence will fail. In initial acquisition, simple single-step mands (e.g., hitting a micro-switch or handing a single icon) should be selected.
3. Rate and Delay of Reinforcement: The replacement behavior must produce immediate and dense reinforcement during early training. If problem behavior produced immediate escape but the replacement request results in a 10-second delay, the client will revert to the problem behavior.
4. Listener Community Compatibility: The replacement behavior must be easily recognized and reinforced by caregivers, teachers, and community members across natural settings.

---

3. Side Effects of Extinction and Mitigation Protocols

Extinction is rarely a smooth process. QBAs must prepare staff and families for predictable side effects to prevent treatment breakdown or accidental reinforcement of escalated responses.

• Extinction Burst: A sudden, temporary increase in the frequency, intensity, or duration of the target behavior immediately following the implementation of extinction. Staff must be trained that an extinction burst is evidence of correct procedural implementation, not treatment failure.
• Extinction-Induced Aggression: The appearance of novel emotional or aggressive responses (e.g., biting, scratching) when previously reinforced responses no longer produce reinforcement.
• Spontaneous Recovery: The sudden reappearance of the target behavior after it has been suppressed or reduced to low rates, occurring without any re-pairing with reinforcement.
• Response Variation: The emergence of novel topographic variations of the target behavior as the learner attempts to produce the lost reinforcer.

Risk Mitigation for QBAs

To safely manage extinction side effects, QBAs should:

• Never implement extinction as a standalone intervention; always pair extinction with dense DRA/FCT.
• Conduct pre-intervention safety assessments and establish clear crisis management plans if extinction bursts involve high-risk self-injury or aggression.
• Train all implementation team members to 100% procedural integrity before launching extinction protocols to avoid intermittent reinforcement of burst behaviors.