11.3 Differential Reinforcement of Alternative & Incompatible Behavior (DRA/DRI)

Differential Reinforcement of Alternative & Incompatible Behavior (DRA/DRI)

Exam Tip: On the QASP-S exam, you will encounter numerous scenario questions asking you to differentiate between Differential Reinforcement of Alternative Behavior (DRA) and Differential Reinforcement of Incompatible Behavior (DRI). The definitive question to ask yourself is: Can the client physically perform both behaviors at the exact same instant in time? If YES, it is DRA. If NO (topographically impossible to emit simultaneously), it is DRI. Furthermore, you must know how to apply Herrnstein's Matching Law and Horner & Day's Response Effort Principle to select effective replacement behaviors.

Within applied behavior analysis, behavior reduction must never occur within an instructional vacuum. Suppressing challenging behavior through punishment or extinction alone is clinically ineffective, ethically suspect, and highly susceptible to relapse. Differential Reinforcement represents the gold standard of humane, evidence-based behavior reduction. By coupling the reinforcement of adaptive, functional repertoires with the extinction or withholding of reinforcement for challenging responses, differential reinforcement transforms behavior reduction into a constructive, educational process.

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Conceptual Foundations of Differential Reinforcement

Differential reinforcement is an operant procedure comprising two simultaneous, interdependent components:

1. Reinforcement of a designated desirable response ($R_{\text{desirable}} \rightarrow S^{R+}$), and
2. Extinction (or reduced/delayed reinforcement) of the target challenging response ($R_{\text{problem}} \rightarrow \emptyset$).

By manipulating relative reinforcement rates, clinicians leverage Herrnstein's Matching Law, which dictates that an organism distributes its behavioral output in direct proportion to the relative rates, immediacy, quality, and magnitude of reinforcement delivered across concurrent operants:

$\frac{B_1}{B_1 + B_2} = \frac{R_1}{R_1 + R_2}$

When the alternative or incompatible behavior ($B_1$) produces immediate, high-magnitude, dense reinforcement ($R_1$), while the problem behavior ($B_2$) contacts zero reinforcement ($R_2 = 0$), the client will systematically allocate their responding almost exclusively to the adaptive alternative.

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Differential Reinforcement of Alternative Behavior (DRA)

Differential Reinforcement of Alternative Behavior (DRA) entails delivering reinforcement contingent upon the emission of a desirable, prosocial behavior that serves as an alternative to the target problem behavior, while placing the problem behavior on extinction.

Function-Based DRA vs. Non-Function-Based DRA

• Function-Based DRA (Functional Communication Training / FCT): The alternative behavior yields the exact same maintaining consequence identified during the FBA. For example, if screaming is maintained by escape from academic demands, the alternative behavior (touching a 'Break' card) produces immediate task removal. Function-based DRA is vastly superior in clinical speed, durability, and social validity.
• Non-Function-Based DRA: The alternative behavior produces an arbitrary, contrived reinforcer unmatched to the maintaining function (e.g., delivering an edible treat for in-seat behavior when out-of-seat running is maintained by peer attention). Non-function-based DRA is substantially less effective because it fails to satisfy the active Motivating Operation (MO).

Clinical ASD Examples of DRA Across Functions

• Social Positive (Attention): A child engages in screaming to gain adult attention. Staff implement DRA: raising a hand or tapping the therapist's shoulder is reinforced immediately with enthusiastic verbal praise and interaction, while screaming contacts planned ignoring.
• Tangible (Access): A learner engages in physical grabbing and hitting when a tablet is set aside. Staff implement DRA: handing a picture icon of the tablet is reinforced with immediate 2-minute tablet access, while grabbing is blocked and contacts extinction.
• Social Negative (Escape): A student engages in desk-sweeping when presented with math worksheets. Staff implement DRA: vocally stating "I need help" is reinforced with immediate teacher assistance and demand reduction, while desk-sweeping results in guided compliance.
• Automatic (Sensory): A client engages in hand-mouthing for oral sensory feedback. Staff implement DRA: chewing on an oral sensory chew-pendant produces access to oral stimulation, while hand-mouthing is neutrally redirected.

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Differential Reinforcement of Incompatible Behavior (DRI)

Differential Reinforcement of Incompatible Behavior (DRI) is a specialized sub-variant of DRA. In DRI, the alternative behavior selected for reinforcement is physically and topographically incompatible with the target problem behavior. It is physically impossible for the human body to emit both behaviors at the exact same instant in time.

The Incompatibility Criterion

To qualify as DRI, the physical mechanics of the replacement response must mutually preclude the problem behavior:

• Problem Behavior: Hand-Flapping (Motor Stereotypy) $\rightarrow$ DRI Replacement: Hands in Pockets or Holding a Weighted Ball. A client cannot physically flap their hands while both hands are fully submerged inside their pant pockets or gripping a ball with both hands.
• Problem Behavior: Out-of-Seat Elopement $\rightarrow$ DRI Replacement: Sitting with Bottom on Chair and Feet on Floor. An individual cannot be out of their seat and simultaneously seated in their chair.
• Problem Behavior: Hand-Biting / Finger-Sucking $\rightarrow$ DRI Replacement: Chewing Sugar-Free Gum or Sucking a Straw. An individual cannot insert their knuckles into their mouth while their jaws are actively occupied chewing gum or drinking.
• Problem Behavior: Pinching / Scratching Therapists $\rightarrow$ DRI Replacement: Clapping Hands or Resting Palms Flat on Desk. A person cannot pinch another person while their palms are pressed flat against a table surface.
• Problem Behavior: Throwing Instructional Materials $\rightarrow$ DRI Replacement: Holding a Clipboard with Both Hands. An individual cannot throw materials with a hand that is securely gripping the clipboard.

DRA vs. DRI: The Operational Test

                  ┌──────────────────────────────────────────────┐
                  │  Can the client physically emit BOTH the     │
                  │  replacement response and the problem        │
                  │  response at the exact same instant in time? │
                  └──────────────────────┬───────────────────────┘
                                         │
                         ┌───────────────┴───────────────┐
                         ▼                               ▼
                      [ YES ]                         [ NO ]
                         │                               │
                         ▼                               ▼
                ┌─────────────────┐             ┌─────────────────┐
                │       DRA       │             │       DRI       │
                │  (Alternative)  │             │  (Incompatible) │
                └─────────────────┘             └─────────────────┘
                Example: Raising hand           Example: Hands in pockets
                while still yelling.            while hitting cannot occur.

Clinical Note: While raising one's hand is a wonderful alternative to shouting out in class, a student can technically raise their hand and shout at the exact same moment. Thus, hand-raising is DRA, not DRI. Conversely, clapping hands makes hitting physically impossible; thus, clapping is DRI.

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Clinical Selection Criteria for Replacement Behaviors

Selecting an inappropriate replacement behavior guarantees treatment failure. The QASP-S must evaluate replacement responses against five empirical criteria:

1. Functional Equivalence

The replacement behavior must access the exact same environmental reinforcer that currently maintains the problem behavior. If a child engages in aggression to escape non-preferred tasks, teaching them to say "cookie" or "look at me" will completely fail to reduce aggression. The response must yield task termination or assistance (e.g., "Break please").

2. The Response Effort Principle (Horner & Day, 1991)

Under Herrnstein's Matching Law, behavior allocation is dictated by response effort (physical and cognitive energy expenditure):

$\text{Response Effort}(\text{Replacement}) \le \text{Response Effort}(\text{Problem Behavior})$

If emitting problem behavior requires 1 second of physical effort (e.g., knocking a paper off a desk), but emitting the replacement response requires navigating three sub-menus on an AAC device, scrolling down, locating a tiny icon, and pressing it, the client will choose the problem behavior every single time. The replacement behavior must be easier, faster, and more efficient than the problem behavior.

3. Current Repertoire vs. Rapid Shapeability

Whenever feasible, select a behavior already present within the client's current motor and vocal repertoire. If a novel topography must be trained, it must be rapidly shapeable using errorless prompting and immediate physical guidance.

4. Social Validity & Community Recognizability

The replacement behavior must be readily understood and reinforced by natural stakeholders—parents, siblings, general education teachers, and peers. An idiosyncratic gesture known only to an ABA technician will fail in inclusive community environments.

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Reinforcement Scheduling: From Acquisition to Systematic Thinning

An effective DRA/DRI intervention progresses through distinct schedule phases:

Phase 1: Initial Acquisition on Continuous Reinforcement (CRF / FR1)

During initial training, the replacement behavior must be placed on a Fixed Ratio 1 (FR1 / Continuous Reinforcement) schedule:

• Every single occurrence of the replacement behavior—whether fully independent or physically prompted—must contact immediate, high-magnitude reinforcement ($< 1-2$ seconds latency).
• Zero Delay: The client must experience immediate reinforcement to build strong contingency awareness.
• Errorless Prompting: Use immediate prompting (e.g., physical prompt to touch break card as soon as the demand is presented) to prevent the problem behavior from occurring.

Phase 2: Systematic Schedule Thinning

An FR1 schedule is unsustainable in natural environments. Once the replacement behavior is firmly established and problem behavior has decelerated by $\ge 80%$, the QASP-S must systematically thin the schedule:

1. Ratio Thinning: Progressively increasing the response requirement before reinforcement is delivered (e.g., FR1 $\rightarrow$ FR2 $\rightarrow$ FR4 $\rightarrow$ VR5), requiring the learner to complete more academic items before earning a break.
2. Delay Thinning: Systematically introducing an elapsed time delay between the emission of the replacement mand and the delivery of the reinforcer (e.g., mand $\rightarrow$ 2-second delay $\rightarrow$ 5-second delay $\rightarrow$ 15-second delay) paired with visual countdowns or "Wait" cards.
3. Delay-and-Denial Tolerance Training (Hanley et al.): Explicitly teaching the learner to tolerate delays ("You can have that in two minutes") and accept denials ("Not right now, but you can have it after lunch") while maintaining calm behavior.

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Combining DRA/DRI with Extinction: The Power of Contrast

In laboratory and translational ABA literature, differential reinforcement exhibits maximum potency when combined with strict functional extinction:

• With Extinction: The contrast in reinforcement density is absolute ($R_{\text{alt}} = 100%, R_{\text{prob}} = 0%$). Problem behavior extinguishes rapidly because it yields zero payoff.
• Without Extinction: If problem behavior continues to produce reinforcement even intermittently ($R_{\text{prob}} > 0$), the matching law dictates that the client will continue emitting problem behavior, particularly when tired, frustrated, or when response effort fluctuates.

What If Extinction Cannot Be Safely Executed?

In community or classroom settings where staff cannot physically block severe aggression or where task escape cannot be completely prevented without dangerous physical struggle, extinction may be unfeasible. In such scenarios, clinicians must create an asymmetrical reinforcement contrast:

1. Reinforcer Quality: Deliver premium, highest-preference reinforcers exclusively for the replacement behavior.
2. Reinforcer Immediacy: Provide instantaneous reinforcement ($< 1$ second) for the alternative response, while imposing an intentional, substantial delay (e.g., 30-60 seconds) on any reinforcer produced by problem behavior.
3. Reinforcer Magnitude: Provide massive magnitude (e.g., 5 minutes of iPad access) for the replacement behavior, compared to minimal magnitude (e.g., 10 seconds of neutral break) following problem behavior.

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Comparative Matrix: Problem Behaviors, Functions, and DRA vs. DRI Replacements

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DRA/DRI Implementation, Prompting, and Thinning Workflow

The following clinical flowchart outlines the systematic implementation of DRA and DRI from baseline FBA through schedule thinning and natural maintenance.