Distinguish Between Motivating Operations and Stimulus Control
If you work in ABA, you’ve likely heard both terms in the same breath: motivating operations and stimulus control. They sound related, they’re both antecedents, and they both affect behavior. But they work in fundamentally different ways, and confusing them can derail your assessment and intervention planning.
Here’s the good news: once you grasp the distinction, you’ll spot it in nearly every behavior you observe. The bad news: misidentifying which one is at play can lead to ineffective prompting, unexpected extinction, and wasted clinical time.
This post will walk you through clear definitions, practical examples, the risks of mixing them up, and how to tell them apart in the clinic. Whether you’re a BCBA planning treatment or a clinician trying to understand why a particular approach isn’t working, this guide will sharpen your thinking.
One-Paragraph Summary
A motivating operation (MO) is an environmental variable that changes how much a consequence is valued right now and alters how likely a behavior is to occur in the moment. A stimulus control relationship exists when a specific cue (called a discriminative stimulus, or Sd) signals that reinforcement is available for a behavior, based on learning history. The core difference: an MO answers “why is this behavior more valuable now?” while stimulus control answers “when or where will this behavior be reinforced?” Think of a hungry child who refuses table work at school (low deprivation, weak MO) but eagerly works after missing breakfast (higher deprivation, stronger MO)—the hunger changes how much the edible reinforcer is worth. Compare that to a child who will only sit at the blue table, not the red one, because sitting at the blue table has always led to reinforcement (stimulus control). Getting this distinction right shapes whether you adjust the pre-session snack or redesign your cues.
Clear Explanation of the Topic
What Is a Motivating Operation?
A motivating operation is an environmental condition that does two things at once: it changes the value of a consequence and shifts how likely a behavior is to happen in that moment.
Imagine you’re thirsty. Water becomes highly valuable to you right now. You’re more likely to search for a water fountain, ask for a drink, or remember where the cooler is. That thirst is an establishing operation—it increases the value of water and evokes water-seeking behavior.
Now imagine you just drank a full bottle of water. The value of water drops sharply, and you stop looking for it. That’s an abolishing operation—it decreases the value and reduces the behavior.
Motivating operations come in two main flavors. Establishing operations (EOs) increase the value of a reinforcer and evoke related behavior. Abolishing operations (AOs) decrease the value and reduce behavior. You can also classify them as unconditioned (built in, like hunger) or conditioned (learned, like how a key becomes valuable when you see a locked door).
What matters most is this: an MO is temporary and state-like. It’s here now, and when the condition changes, the MO fades.
What Is Stimulus Control?
Stimulus control is different. It’s not about value; it’s about when and where a behavior is likely to pay off.
A discriminative stimulus (Sd) is a cue that signals “if you do this behavior right now, you’ll get reinforced.” An S-delta (SΔ) signals the opposite: “if you do this behavior now, there’s no reinforcement.”
The child learns through history: when the teacher says “sit,” sitting gets rewarded. When the teacher is quiet, sitting doesn’t. Over time, the teacher’s request becomes a reliable cue—stimulus control develops.
Stimulus control is built through a history of differential reinforcement. You reinforce the behavior in the presence of the Sd and don’t reinforce it in the presence of the SΔ. The more consistently you do this, the stronger the control.
Unlike an MO, stimulus control is persistent and learned. It sticks around because the cue has been paired with reinforcement many times.
The Functional Difference
Here’s where it gets clear: an MO answers the question why is this more valuable now? Stimulus control answers when or where will this work?
An MO changes the desirability of an outcome. Stimulus control signals the availability of that outcome based on learned associations.
You can have stimulus control without an MO (a cue for sitting can be strong even if the child isn’t hungry), and you can have an MO without a specific Sd (hunger can evoke eating-related behavior in any context). But they often work together.
Timing and Learning History
One more key difference: MOs are transient; stimulus control is persistent.
A motivating operation shifts with the state of the person. Hunger comes and goes. Fatigue comes and goes. But a discriminative stimulus—a visual cue, a verbal instruction, the presence of a certain person—persists because it’s embedded in the learning history.
That’s why you can teach stimulus control and expect it to last, but you can’t expect an MO to do the same.
Why This Matters
Getting the Diagnosis Wrong Has Real Costs
Imagine you’re working with a student who seems unmotivated for math tasks. You notice he does math faster when you offer a snack beforehand. You naturally think “I need to pair the snack with the task so it becomes a cue for working.” So you start always saying “snack time, then math” and following up with a snack.
But what if the real issue is that he’s not hungry enough right now? You’ve mistaken an MO problem for a stimulus control problem. You’ve created a signal, but the underlying value isn’t there.
Or the reverse: a student only works when her favorite peer is present. You assume the peer’s presence is just a cue, so you fade the peer out. But peer presence was actually raising the value of the reinforcer (social motivation)—an MO, not just a signal. When you fade it, the whole system collapses because the behavior was never really under stimulus control; it was under MO control.
These mix-ups waste time and can actually make behavior worse. When you prompt a behavior under low MO, you risk extinction—the behavior fails, reinforcement doesn’t come, and the behavior weakens. When you ignore MOs and rely only on signals, you set up situations where the cue is present but the learner doesn’t care.
Intervention Planning Changes Based on the Distinction
If the problem is an MO, your intervention targets value. You might adjust when sessions happen, manage deprivation or satiation, or manipulate access to preferred items.
If the problem is stimulus control, your intervention targets the signal. You might use clearer cues, practice discrimination training, or fade prompts more carefully.
The right diagnosis makes the difference between a working plan and one that stalls.
Ethics and Autonomy
This matters ethically too. Manipulating MOs—especially through deprivation or access restriction—requires informed consent, documented justification, and close supervision. It’s a bigger intervention.
Stimulus control training, when done well, can be less restrictive and more transparent: you’re teaching the person to recognize a cue, not adjusting their internal state.
Key Features and Defining Characteristics
Motivating Operations
MOs alter momentary value and current behavior frequency. They make a consequence more or less desirable right now. They have evocative effects (increasing behavior when you need the reinforcer) and abative effects (decreasing behavior when the reinforcer’s value drops). MOs can be unconditioned—like hunger or pain—or conditioned, like the value of a key when a door is locked.
Stimulus Control
An Sd signals the availability of reinforcement based on learning history. It sets the occasion for a response. An SΔ signals non-availability. Stimulus control emerges from differential reinforcement: reinforce in the presence of the Sd, withhold reinforcement in the presence of the SΔ.
Boundary Conditions
MOs affect the “why now.” Stimulus control affects the “when, where, or with whom.”
MOs can shift in seconds or minutes. Stimulus control requires learning and reflects a stable discrimination.
You can’t force stimulus control to develop faster by just wanting it to; it depends on consistent contingencies. And you can’t eliminate an MO just by ignoring it; if someone is hungry, they’re hungry.
When You Would Use This in Practice
Recognizing When to Target an MO
Use MO-focused interventions when the learner’s current motivation is the bottleneck. If a child is sluggish and disengaged because she missed breakfast, adjusting her hunger level before the session makes sense. If a student will only work for social reinforcement when peers are around, ensuring appropriate access to peer interaction as a contingency addresses the MO.
Common MO-focused strategies include pre-session access (giving a few minutes of preferred activity to satiate before work), deprivation protocols (managing access to increase value), and context changes (holding sessions when the MO is naturally more favorable).
Recognizing When to Target Stimulus Control
Use stimulus control interventions when the learner’s motivation is adequate but the signal is weak or ambiguous.
If a student can focus when you use a verbal cue (“ready to work?”) but not when you just gesture, you’re building stimulus control—the words are becoming a clearer Sd. If a student generalizes a response to the wrong cue (e.g., sits whenever anyone enters the room, not just when the teacher does), you need discrimination training to sharpen Sd control.
Stimulus control strategies include pairing cues with reinforcement consistently, using clear discriminations (bright Sd vs. distinct SΔ), fading prompts that support the Sd, and teaching across contexts so the Sd works reliably.
How to Choose During Assessment
Look at timing and context.
Does the behavior change when you adjust the learner’s internal state (tired vs. rested, hungry vs. satiated, socially isolated vs. with peers)? That points to an MO.
Does the behavior change reliably based on the presence or absence of a specific cue or person, regardless of motivation? That points to stimulus control.
Often both are happening; your job is to figure out which one is the main problem and address that first.
Examples in ABA
Example 1: Breakfast, Hunger, and Table Work
A child arrives at school after a large breakfast. For the first hour, she refuses to engage in table work even though you offer her preferred edible reinforcers. Later, after about two hours without eating, she eagerly sits down for the same tasks with the same reinforcers.
The MO: Food deprivation has increased; the value of edible reinforcers is now higher. The hunger level has changed what the consequence is worth.
The stimulus control: When you sit at the blue table and say “puzzle time,” that’s the Sd. The child has learned that puzzles at the blue table lead to rewards.
What to do: If motivation is the issue, adjust the session timing so she’s appropriately hungry, or use a non-edible reinforcer when she’s satiated. If the cue is the issue, practice the “puzzle time” signal at the blue table consistently so it becomes a strong Sd.
Example 2: Peer Presence and Attention-Seeking
A teenager engages in disruptive behavior—loud comments, off-task remarks—when peers are present in the classroom. When working one-on-one with staff, the behavior rarely happens.
The MO: The presence of peers has increased the value of peer attention. The opportunity to get peer reactions is more valuable right now.
The stimulus control: Peers present might also signal that disruptive behavior will get reinforced (has been reinforced in the past). The peer context is an Sd for the behavior.
What to do: You could manipulate the MO by managing peer access or ensuring appropriate peer interaction during appropriate times. You could also target stimulus control by teaching the student what peer presence actually signals now (reinforcement for on-task behavior, not disruption) through consistent contingencies.
Examples Outside of ABA
Example 1: Coffee and the Morning Habit
You’re more likely to buy coffee in the morning when you’re tired. You’re also more likely to buy it when you pass a coffee shop with an illuminated “Open” sign and a menu visible in the window.
The MO: Morning fatigue increases the value of caffeine. You need coffee more right now.
The stimulus control: The lit sign and visible menu are cues that signal “coffee is available and ready to buy.” Even if you weren’t tired, a clear, appealing sign makes buying more likely because it signals availability.
Both happen together, but they’re doing different jobs.
Example 2: Promotional Emails and Discounts
You’re more likely to open a promotional email when you’re actively looking for a deal. You’re also more likely to open it when the subject line contains a brand name you recognize and trust.
The MO: Your current desire to save money increases the value of discount information.
The stimulus control: The familiar brand name in the subject line is a cue that signals “this email probably contains a good deal.” It’s learned through experience—emails from this brand have usually been worth opening.
Again, value and signaling are both present but distinct.
Common Mistakes and Misconceptions
Mistake 1: Treating MOs and Stimulus Control as the Same Thing
Both are antecedents, and both affect behavior, so it’s easy to lump them together. But they change behavior through different mechanisms. An MO changes what the person wants. An Sd signals when they can get it. Confusing them leads to interventions that address the wrong problem.
Mistake 2: Assuming a Cue Always Means Stimulus Control
Just because you’ve introduced a visual cue, a sound, or a person doesn’t mean stimulus control has developed. The learner has to have a history of reinforcement tied to that cue. If you point to a picture and say “sit,” and the learner hasn’t practiced sitting when you point to that specific picture many times, the picture isn’t a strong Sd yet.
Mistake 3: Forgetting That MOs Change Reinforcer Effectiveness, Not Just Behavior Rate
An MO doesn’t just make behavior happen more often—it changes how valuable the consequence is. If you don’t understand this, you might keep using the same reinforcer even when its value has dropped. The behavior looks like it’s slowing down, but you’re blaming something else.
Mistake 4: Treating Transient States as Learned Stimulus Control
If a behavior only happens when the person is tired, hungry, or socially isolated, you’re likely looking at an MO, not a learned signal. Stimulus control is about learned history, not temporary states.
Three Quick Diagnostic Questions
When you observe a behavior, ask yourself:
- Does the value of the consequence change the behavior? (If yes, suspect an MO.)
- Does the presence or absence of a specific cue change the behavior? (If yes, suspect stimulus control.)
- What’s the learning history? (Has this cue been paired with reinforcement many times?)
Ethical Considerations
Risks of MO Manipulation
Manipulating motivating operations—especially through deprivation, restriction, or other access-limiting strategies—is a bigger intervention than it might sound. It requires informed consent from the client or guardian, documented justification based on functional assessment, close supervision, and regular monitoring for adverse effects.
Deprivation-based strategies are not off the table, but they must be justified, least restrictive alternatives must be considered first, and safeguards must be in place.
Client Dignity and Autonomy
Always ask: Is there a way to achieve the same behavioral outcome while preserving the person’s choice and dignity? Can we use an EO (like arranging a preferred activity before work) instead of an AO (restricting access)? Can we build stimulus control through clear, transparent teaching instead of relying on hidden MO manipulations?
The strongest interventions are ones where the person understands what’s happening and consents to it.
What Supervisors Should Do
If you’re supervising others and reviewing plans that manipulate MOs, scrutinize them carefully. Ask to see the functional assessment that justifies the approach. Require written protocols that specify how long the manipulation will last, how effects will be monitored, and what the exit criteria are. Ensure that any deprivation-based strategy has ethics review and is being documented meticulously.
Practice Questions
Question 1: A learner only completes math worksheets when offered a snack immediately afterward and does not complete them when no snack is mentioned. Is the snack functioning as a motivating operation, a discriminative stimulus, or both?
Correct Answer: Both. The snack expectation acts as an MO (increases the value of completing the worksheet so they can access the snack) and the verbal mention may serve as an Sd if it signals that reinforcement is available for completion. This shows that a single antecedent can have multiple functions at once.
Question 2: Which of the following best indicates a motivating operation rather than stimulus control?
A) Behavior occurs only in the presence of a specific cue. B) Behavior increases after several hours without sleep. C) Behavior persists after reinforcement history.
Correct Answer: B. Sleep deprivation is an establishing operation—it changes the value of certain reinforcers (rest, quiet, comfort) and increases related behavior right now. Options A and C point toward stimulus control or reinforcement history.
Question 3: During a probe, a child’s request rate rises after you remove preferred toys from the room. Which intervention targets the MO?
Correct Answer: Introducing brief, contingent access to preferred toys following appropriate requests (or otherwise modifying the deprivation state). This directly addresses the value by altering the MO. Interventions that only change prompts or refine the Sd would not address the underlying motivational state.
Question 4: Which teaching strategy builds stimulus control?
A) Repeatedly pairing a cue with reinforcement until the learner responds mainly in the presence of the cue. B) Temporarily increasing deprivation to make reinforcement more potent.
Correct Answer: A. Repeated pairing and differential reinforcement establish discriminative control. Option B changes an MO, not stimulus control.
Question 5: You observe that a parent’s neutral tone produces compliance after weeks of consistent, positive consequences following that tone. What learning history feature likely produced this stimulus control?
Correct Answer: Differential reinforcement history. The parent’s neutral tone became an Sd because it was consistently paired with reinforcement. This emphasizes that stimulus control is learned through contingent history, not through immediate value shifts.
FAQs
Q: What is the simplest way to tell an MO from stimulus control?
A: Test whether changing the learner’s state changes behavior (suspect an MO) versus whether changing the cue or context changes behavior (suspect stimulus control). If a child refuses to work because she just ate a large meal, try working with her later when she’s hungrier—if behavior improves, an MO was likely the issue. If a child only sits when you use a specific verbal cue, but sits reliably when you use that cue regardless of hunger, stimulus control is likely at play.
Q: Can the same stimulus be both an MO and an Sd?
A: Yes. A stimulus can increase the value of a consequence (MO function) and signal that reinforcement is available (Sd function). The smell of food can be an establishing operation for eating-related behavior and, if previously paired with a meal, can also signal that food is coming. Assessment and data collection help you figure out which function is primary or if both are contributing.
Q: How do I safely test for an MO in the clinic?
A: Design brief, ethically sound probes that manipulate the condition (hunger, social access, or preferred item availability) and observe changes in the target behavior without altering reinforcement contingencies. Hold a session before a snack and note compliance rates, then hold a similar session after brief pre-session toy access and note rates again. Always have safeguards: ensure no harm, get consent, monitor for distress, and document the rationale and outcome. Consult your supervisor before running deprivation-based probes.
Q: How long does stimulus control take to build?
A: It varies. There’s no universal timeline. It depends on how consistently you reinforce in the presence of the Sd and withhold reinforcement in the presence of the SΔ, how distinct your Sd and SΔ are, and individual learner factors. Some learners show rapid discrimination in a few sessions; others need weeks of practice. The key is consistent, clear contingencies and patience.
Q: Is it ethical to use MOs like deprivation to change behavior?
A: Yes, if done thoughtfully. Deprivation-based strategies can be ethical when they are justified by functional assessment, chosen after less restrictive alternatives have been tried, implemented with informed consent, monitored closely, and supervised rigorously. Always document your decision, the safeguards you’ve put in place, and the effects you observe. When in doubt, consult your supervisor or ethics committee.
Q: What are quick signs that a behavior is under stimulus control?
A: The behavior reliably occurs in the presence of a cue and doesn’t occur (or occurs at much lower rates) without it. There’s a clear, consistent reinforcement history tied to that cue. The behavior holds up across multiple days and contexts because it’s based on learned associations, not temporary states.
Q: Should I always try to remove MOs before teaching new skills?
A: Not always. Sometimes an MO is your friend. Mild food deprivation before a snack-based session can increase motivation and speed learning. Social deprivation before peer-based reinforcement can increase engagement. The key is mild, intentional, monitored, and ethical. Always weigh least-restrictive alternatives and align with the learner’s dignity and wellbeing.
Related Concepts
Understanding motivating operations and stimulus control is easier when you connect them to related ideas.
Functional assessment is the tool you use to distinguish whether a behavior is driven by MOs or by stimulus control. During an FA, you manipulate conditions and measure the behavior’s response to identify what’s maintaining it.
Establishing and abolishing operations (EO and AO) are subtypes of MOs. An EO increases reinforcer value; an AO decreases it. Both are motivating operations.
Discriminative stimulus (Sd) is the formal term for the cue in stimulus control. It signals reinforcement availability.
Generalization and discrimination are the outcomes of stimulus control training. When you want a behavior to occur under a wider range of cues, you’re promoting generalization. When you want it to happen only in specific contexts, you’re sharpening discrimination.
Antecedent interventions can target either MOs or stimulus control. Pre-session manipulations target MOs; cue training and fading target stimulus control.
Key Takeaways
Motivating operations change the current value of a consequence and alter momentary behavior probability. Stimulus control signals when a response will be reinforced, based on a history of learning.
Effective practice requires assessing both and recognizing that they can work together or independently. Simple probes help differentiate MO effects from stimulus control before you commit to an intervention.
Ethical practice demands that you respect consent, document your decisions, and choose the least restrictive path whenever possible.
Closing Summary
The MO–Sd distinction is one of the most important you’ll make in ABA. Motivating operations change how much a reinforcer is valued right now. Stimulus control signals when or where a behavior will pay off, based on learned history. They are different processes with different solutions, and getting the diagnosis right shapes your whole intervention.
As you build your understanding, keep these practices in mind: gather functional assessment data before you guess, be transparent and ethical when you manipulate MOs, and always prioritize the learner’s dignity and autonomy.
