Building motivating operations and discriminative stimuli into interventions

Domain B asks what an MO or an SD is. Domain G asks how you arrange them on purpose so an intervention works.

Why it matters

A reinforcer only works if it is valuable right now, and a response only shows up reliably if something tells the learner that reinforcement is available. When a program stalls, the cause is often antecedent. A child fresh from unlimited tablet time will not work for more of it, and a student who cannot tell when the teacher is free will ask at the wrong moments.

Practice items for this task describe an intervention and ask which antecedent change targets motivation and which targets stimulus control.

Key ideas

Arranging MOs

• Establishing operations (EOs) raise value. Restricting free access to a specific, nonessential item between sessions can make it a stronger reinforcer during sessions. Keep the restriction limited and agreed with the client or family, and never apply it to meals, water, sleep, or basic rights.
• Abolishing operations (AOs) lower value. Noncontingent reinforcement (NCR) delivers the maintaining reinforcer on a time-based schedule, so the learner has less reason to engage in problem behavior to get it. Most of NCR's effect is usually credited to this abolishing effect.
• Reducing aversiveness is an MO change too. For escape-maintained behavior, shorter tasks, mixed-in easy items, and choices lower the value of escape.
• Contrive MOs for mand training. Mands are controlled mainly by MOs, so you need moments when the learner actually wants something. You can capture naturally occurring MOs (incidental teaching) or contrive them: give a toy without its batteries, serve cereal without a spoon, or interrupt a familiar routine. These are transitive CMOs: one stimulus makes another valuable.

Arranging SDs

• Stimulus control is built through differential reinforcement. Reinforce the response in the presence of the SD and withhold reinforcement in the presence of the S-delta. Over time the SD evokes the response and the S-delta does not.
• Signal availability when reinforcement cannot always be delivered. In a multiple schedule, one stimulus (for example, a green card) signals that a communication response will be honored and another (a red card) signals that it will not. This is a common way to thin functional communication training.
• Plan for the natural SD. Start with salient cues if needed, then transfer control to stimuli found at home, school, or work.

Combine them. An SD evokes a response only when a relevant MO is in effect. The strongest plans make the reinforcer valuable and make its availability clear.

Definitions

• Motivating operation (MO): an environmental variable that changes how effective a consequence is and changes how often behavior that has produced that consequence occurs right now.
• Discriminative stimulus (SD): a stimulus in whose presence a response has been reinforced and in whose absence it has not, so it now evokes that response.
• S-delta (SΔ): a stimulus in whose presence a response has not been reinforced, so the response becomes less likely when it is present.
• Contrived motivating operation: a teaching arrangement that briefly makes an item or action valuable, such as withholding a needed part, so a mand for it can be prompted and reinforced.
• Noncontingent reinforcement (NCR): delivery of a known reinforcer on a fixed-time or variable-time schedule, independent of behavior, which typically lowers that reinforcer's value as a consequence for problem behavior.
• Multiple schedule: two or more schedules that alternate, each signaled by its own distinct stimulus.

Examples from a session

Common mistakes / exam traps

• Labeling a signal as an MO. A card, light, or lanyard that signals whether a reinforcer is available is an SD (or S-delta). It does not change how much the learner wants the reinforcer.
• Leaving mands under verbal SD control. If you always ask "What do you want?" first, the learner may request only when asked. Fade the question and arrange real MOs.
• Teaching when satiated. Running mand trials right after free access to the item undermines the session. Check the MO first.
• Using deprivation that crosses ethical lines. Restrict only specific, nonessential reinforcers, with the client's or caregivers' agreement, and never basic needs.

Quick check

Related topics

• Motivating operations in action (B.16)
• Motivating operations vs. stimulus control (B.17)
• Recognizing stimulus control (B.12)
• The verbal operants: mand, tact, echoic, intraverbal, and more (B.19)
• Time-based reinforcement schedules, such as fixed-time (G.3)
• Teaching simple and conditional discriminations (G.6)