6.3 Differential Reinforcement Procedures (DRA, DRO, DRI, DRL, DRH)

Differential Reinforcement Procedures (DRA, DRO, DRI, DRL, and DRH)

Differential Reinforcement is one of the most widely used, ethically sound, and effective evidence-based strategies in Applied Behavior Analysis for reducing challenging behaviors. At its core, differential reinforcement involves applying two fundamental principles simultaneously: delivering positive reinforcement for a specific, desirable behavior (or omission of behavior) while withholding reinforcement (extinction) for the target problem behavior. By shifting the balance of reinforcement toward positive, adaptive responses, technicians systematically reduce problem behaviors without relying on punishment. For the Applied Behavior Analysis Technician (ABAT), mastering the distinctions among DRA, DRI, DRO, and DRL is essential for correct field implementation and certification success.

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1. Differential Reinforcement of Alternative Behavior (DRA)

DRA involves reinforcing a desirable alternative behavior that serves the same function as the target problem behavior, while placing the problem behavior on extinction.

• Mechanism: The alternative behavior does not have to be physically incompatible with the target behavior, but it must be functional and socially appropriate.
• Integration with FCT: DRA is the primary schedule used during Functional Communication Training (FCT).
• Clinical Example: A child screams (target behavior) to gain access to a snack (tangible function). Under a DRA schedule, screaming is ignored (extinction), and the child is taught to sign "SNACK" (alternative behavior). Signing "SNACK" produces immediate access to food.

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2. Differential Reinforcement of Incompatible Behavior (DRI)

DRI is a specialized variation of DRA in which the alternative behavior selected for reinforcement is topographically incompatible with the problem behavior. That is, the client physically cannot perform both the target behavior and the replacement behavior at the exact same moment.

• Mechanism: Reinforcing an incompatible motor response physically prevents the occurrence of the challenging behavior.
• Clinical Example: A client engages in repetitive hand-biting. Under a DRI procedure, the technician reinforces keeping hands inside pockets or holding a sensory fidget tool with both hands. Because the client cannot bite their hand while both hands are firmly inside pockets, hand-biting is physically precluded.

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3. Differential Reinforcement of Other Behavior (DRO)

DRO—also referred to as Differential Reinforcement of Zero Rates or Omission Training—delivers reinforcement whenever the target challenging behavior has not occurred during a specified interval of time. Reinforcement is contingent on the absence of the problem behavior.

Sub-types of DRO Schedules

1. Fixed-Interval DRO (FI-DRO): The technician sets a fixed timer (e.g., 4 minutes). If the target behavior does not occur throughout the 4-minute window, reinforcement is delivered at the 4-minute mark.
2. Variable-Interval DRO (VI-DRO): The technician delivers reinforcement at varying interval durations that average out to a target time (e.g., average 4 minutes), making reinforcer delivery less predictable.
3. Resetting vs. Non-Resetting Timers:
   • Resetting Timer: If the target behavior occurs at minute 2 of a 5-minute interval, the technician immediately resets the timer back to 5 minutes.
   • Non-Resetting Timer: If the target behavior occurs at minute 2, reinforcement is withheld at minute 5, but the timer simply finishes its current cycle before starting the next 5-minute interval.

Calculating Initial DRO Intervals

To ensure the client experiences success, the initial DRO interval must be set equal to or shorter than the baseline Inter-Response Time (IRT). $\text{Baseline IRT} = \frac{\text{Total Session Duration}}{\text{Total Count of Target Behavior}}$

• Example: If a client engages in aggression 12 times during a 60-minute baseline observation, the average IRT is 5 minutes ($60 \div 12 = 5$). The technician should set the initial DRO interval at 4 minutes (below baseline IRT) to guarantee frequent opportunities for reinforcement.

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4. Differential Reinforcement of Low Rates of Behavior (DRL)

DRL is used when a behavior is acceptable or even desirable at low or moderate rates, but becomes problematic or disruptive when occurring too frequently.

• Mechanism: DRL does not aim to eliminate the behavior completely; rather, it systematically reduces the frequency or rate of occurrence.
• Variations:
  • Full-Session DRL: Reinforcement is delivered at the end of a session if total responses are at or below a specified limit (e.g., fewer than 3 hand-raises during a 30-minute lecture).
  • Spaced-Responding DRL: Reinforcement is delivered only if a specified minimum amount of time has elapsed since the previous response (increasing IRT).
• Clinical Example: A student raises their hand to answer questions 25 times per class period, monopolizing class time. Under DRL, if the student raises their hand 5 times or fewer per period, they earn a special privilege at the end of class.

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Comprehensive Differential Reinforcement Comparison Matrix

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Implementation Guidelines for ABAT Technicians

1. Precise Timing: For DRO procedures, use a dedicated countdown timer. Deliver reinforcement immediately when the interval expires if no target behavior occurred.
2. Avoid Momentary DRO Pitfalls: Ensure you are running an interval DRO (behavior absent across the entire interval) rather than checking only at the moment the timer rings.
3. Schedule Thinning: Once a client achieves 80-90% success at an initial interval, the supervising QBA/BCBA will systematically thin the schedule by increasing interval length (e.g., moving from 3-minute DRO to 5-minute DRO).

Differential Reinforcement of High Rates (DRH)

DRH reinforces responses that occur at or above a specified rate within an interval. It is used when the clinical goal is to increase a desirable behavior that already occurs but at insufficient frequency (for example, increasing the rate of social initiations or work task completions).

ABATs implement the exact DRH interval and rate criteria written by the supervisor and never invent rate thresholds. If the learner's rate is consistently below criterion, report the data rather than changing the schedule independently.