What Is Response Blocking?
Response blocking involves physically preventing the completion of a target behavior by placing a barrier between the individual and the completion of the response. Unlike physical restraint, which restricts the individual's overall movement, response blocking targets a specific behavior and prevents only that particular motor sequence from being completed.
The procedure was first examined in applied research by Lerman and Iwata (1996), who studied its effects on self-injurious behavior. Since then, response blocking has been applied to a wide range of topographies, including stereotypic behaviors, pica, elopement, and dangerous self-stimulatory behaviors.
Behavioral Mechanisms
Response blocking reduces behavior through several potential mechanisms:
- Extinction of automatic reinforcement: By preventing the response from being completed, the individual does not access the sensory reinforcement that maintains the behavior. Over time, this disruption in the response-reinforcer contingency leads to a decrease in the behavior.
- Punishment effect: The physical contact involved in blocking may function as a punisher for some individuals, particularly if the physical interruption is aversive.
- Combined effects: In many cases, both mechanisms operate simultaneously, making it difficult to isolate which one is primarily responsible for behavior reduction.
Understanding which mechanism is at work is clinically important because it affects how you classify the procedure ethically and procedurally. If response blocking functions primarily as punishment, additional ethical safeguards and consent procedures may be required.
Implementing Response Blocking
Procedural Components
- Define the target behavior operationally: Clearly specify the motor movement you are blocking so that all implementers respond consistently.
- Position yourself appropriately: Maintain proximity to the individual so that blocking can occur immediately when the behavior is initiated.
- Block promptly and calmly: As soon as the individual begins the target behavior, place your hand or arm between the individual and the completion of the response. Use the minimum physical contact necessary.
- Maintain a neutral demeanor: Avoid providing verbal reprimands, excessive eye contact, or emotional reactions during the block. Minimize social interaction to avoid confounding the procedure with attention.
- Release immediately: Once the response is interrupted, remove the physical block. Do not maintain contact beyond what is needed to stop the behavior.
- Redirect to an alternative activity: Following the block, prompt the individual to engage in an appropriate alternative behavior and reinforce compliance.
Consistency Requirements
Response blocking is most effective when implemented consistently across every occurrence of the target behavior. Intermittent blocking can lead to an intermittent reinforcement schedule for the automatically maintained behavior, potentially making it more resistant to change.
Clinical Applications
Stereotypic Behavior
Response blocking is frequently used for repetitive motor stereotypies such as hand flapping, body rocking, or object manipulation. The practitioner physically prevents the motor sequence, thereby blocking access to the sensory input the behavior produces.
Pica
For individuals who ingest non-food items, response blocking involves intercepting the hand-to-mouth movement before the item reaches the mouth. This application often requires very close proximity and rapid response times from the implementer.
Self-Injurious Behavior
When self-injury is maintained by automatic reinforcement, response blocking prevents the individual from contacting the sensory stimulation produced by the behavior. For head-hitting, this might involve placing a hand between the individual's hand and head.
Limitations and Concerns
- Response effort for implementers: Response blocking requires constant vigilance and physical proximity. In many settings, maintaining this level of attention for extended periods is impractical.
- Potential for escalation: Some individuals may escalate their behavior when blocked. This can include increased intensity of the target behavior, emergence of new problem behaviors, or aggression toward the person blocking.
- Extinction bursts: If the procedure functions as extinction of automatic reinforcement, expect an initial increase in the rate, intensity, or duration of the behavior before it decreases.
- Reinforcement through physical contact: For some individuals, the physical contact involved in blocking may itself be reinforcing, particularly if the individual's behavior is also sensitive to tactile stimulation or social attention.
- Difficulty with generalization: Behavior may return in settings where response blocking is not in place, making generalization planning essential.
Pairing Response Blocking with Other Procedures
Response blocking is rarely used as a standalone intervention. Best practice involves combining it with reinforcement-based procedures such as NCR (to reduce motivation for automatic reinforcement), DRA (to teach and reinforce alternative behaviors that produce similar sensory input), and environmental enrichment (to provide ongoing access to matched stimulation that competes with the target behavior).
BCBA Exam Relevance
The BCBA exam may ask you to identify response blocking from a scenario, explain whether it functions as extinction or punishment in a given context, describe procedural considerations, and evaluate its appropriateness relative to other interventions. Be prepared to discuss how to determine whether blocking is functioning as an aversive procedure and the ethical implications of that determination.