ABA Therapy
Reinforcement schedules in ABA are rules that determine when and how often a behavior receives reinforcement. A child learning a new communication skill might initially receive reinforcement after every correct response. As the skill becomes stronger, reinforcement may occur less often or according to a specific number of responses or period of time.
Choosing an appropriate schedule can affect how quickly a skill develops, how consistently a child responds, and whether the behavior continues when reinforcement becomes less frequent. ABA therapists adjust reinforcement schedules according to the target behavior, the child’s progress, and the situations where the skill should eventually occur naturally.
Key Takeaways
- Reinforcement schedules determine when a behavior receives reinforcement, ranging from every correct response to reinforcement based on response numbers or time intervals.
- The four basic intermittent schedules are fixed ratio, variable ratio, fixed interval, and variable interval, and each can produce different response patterns.
- ABA therapists adjust and thin reinforcement schedules over time to support skill acquisition, steady responding, maintenance, and greater independence.
What Is a Reinforcement Schedule in ABA?
A reinforcement schedule in ABA is a rule that specifies when reinforcement becomes available following a target behavior. The schedule may reinforce every correct response or only selected responses based on several behaviors or the passage of time.
For example, a child learning to request a toy might receive access to the toy every time they make an appropriate request. Once the behavior becomes more consistent, other forms of reinforcement may occur less frequently while the natural outcome of requesting continues to support the skill.
Reinforcement schedules are based on the principles of operant conditioning. In ABA therapy, therapists use them to help strengthen desired behaviors and determine how reinforcement should change as learning progresses.
It is also important to remember that reinforcement means a consequence increases future behavior. Positive reinforcement adds something following a behavior, while negative reinforcement removes or reduces something. Negative reinforcement is not another term for punishment.
Families can learn more about how preferred outcomes strengthen behavior in Nurturing Nests’ guide to positive reinforcement for autism.
What Is the Difference Between Continuous and Intermittent Reinforcement?
The two broad categories of reinforcement schedules are continuous reinforcement and intermittent reinforcement.
Continuous Reinforcement
A continuous reinforcement schedule, often written as CRF, provides reinforcement after every occurrence of the target behavior.
Suppose a child is learning to say “help.”
During early skill acquisition:
Child appropriately asks for help → reinforcement occurs every time.
This consistent pattern can make the relationship between the behavior and its outcome easier to learn.
Continuous reinforcement is often useful when a skill is new, but it may not be practical or necessary forever. In everyday life, most behaviors do not receive an additional programmed reinforcer after every occurrence.
Intermittent Reinforcement
With intermittent reinforcement, also called partial reinforcement, only some occurrences of the behavior produce the programmed reinforcer.
As a child becomes more successful, the therapy team may gradually move from continuous reinforcement toward an intermittent schedule.
Intermittent reinforcement can make reinforcement more similar to everyday conditions and help established behaviors continue even when an additional reinforcer is not available after every response.
The four basic intermittent schedules combine two dimensions:
- Ratio vs. interval
- Fixed vs. variable
In basic reinforcement schedules, ratio schedules depend on the number of responses, while interval schedules depend on elapsed time.
What Are the Four Basic Schedules of Reinforcement?
The four primary intermittent schedules are fixed ratio, variable ratio, fixed interval, and variable interval.
| Schedule | Reinforcement Is Based On | Predictable? | Simple Example |
| Fixed Ratio (FR) | Number of responses | Yes | Reinforcement after every 5 correct responses |
| Variable Ratio (VR) | Varying number of responses | No | Reinforcement after an average of 5 responses |
| Fixed Interval (FI) | First qualifying response after a set time | Yes | Reinforcement for the first response after 10 minutes |
| Variable Interval (VI) | First qualifying response after varying time periods | No | Reinforcement for the first response after intervals averaging 10 minutes |
Understanding these differences makes the schedule names much easier to remember.
Ratio = responses.
Interval = time.
Fixed = predictable.
Variable = changing or unpredictable.
What Is a Fixed Ratio Schedule?
A fixed ratio schedule reinforces a specific number of responses.
For example:
FR 5 = reinforcement after every fifth qualifying response.
Suppose a learner is practicing math problems and receives a token after five correct responses. After earning the token, the count starts again toward the next five responses.
Fixed ratio schedules often produce relatively high rates of responding because each additional response moves the learner closer to reinforcement.
They can also produce a post-reinforcement pause, where responding briefly slows after the reinforcer is delivered before increasing again.
The size of the ratio matters. Requiring five responses is very different from requiring fifty. ABA therapists increase requirements carefully rather than suddenly placing a large amount of work between reinforcement opportunities.
What Is a Variable Ratio Schedule?
A variable ratio schedule provides reinforcement after a changing number of responses that averages around a planned value.
For example, a VR 5 schedule might provide reinforcement after:
3 responses → 7 responses → 4 responses → 6 responses
The average is five, but the learner cannot predict exactly which response will produce reinforcement.
In a variable ratio schedule, reinforcement follows a changing number of responses around a specified average.
Variable ratio schedules are associated with high, steady responding because reinforcement remains possible but unpredictable.
In ABA therapy, a variable schedule may sometimes be introduced after a skill has become well established. It can help move a behavior away from needing reinforcement after a predictable number of responses.
However, unpredictability is not automatically better. The child, target behavior, current reinforcement history, and treatment goal all matter.
What Is a Fixed Interval Schedule?
A fixed interval schedule makes reinforcement available for the first qualifying response after a fixed period of time has passed.
For example:
FI 5 minutes = once five minutes have passed, the next qualifying response can receive reinforcement.
This does not mean reinforcement automatically occurs every five minutes. A response must still occur after the interval has ended.
Imagine a learner is practicing an appropriate help request. Under an FI 5-minute schedule, once five minutes have elapsed since the previous reinforcement, the next qualifying help request can produce reinforcement. A request made before the interval ends does not satisfy the schedule requirement.
This distinction is important because an interval schedule is not the same as requiring someone to perform a behavior continuously for a set amount of time.
Fixed interval schedules can produce a pattern where responding is slower immediately after reinforcement and increases as the next interval nears. This is sometimes called a scalloped response pattern.
What Is a Variable Interval Schedule?
A variable interval schedule makes reinforcement available after changing periods of time.
For example, a VI schedule averaging five minutes might use intervals of:
3 minutes → 7 minutes → 4 minutes → 6 minutes
Once each interval has elapsed, the next qualifying response can produce reinforcement.
For example, a therapist might arrange reinforcement for the first qualifying independent response after each variable interval has elapsed. The interval lengths change, but reinforcement still depends on a response occurring after the interval requirement has been met.
Because the learner cannot predict exactly when reinforcement becomes available, variable interval schedules tend to produce steadier responding than fixed interval schedules.
The important distinction is that time determines when reinforcement becomes available, but the qualifying behavior must still occur.
How Do the Four Reinforcement Schedules Affect Responding?
Different reinforcement schedules can produce different response patterns.
| Schedule | Common Response Pattern |
| Fixed Ratio | High responding with possible pauses after reinforcement |
| Variable Ratio | High, relatively steady responding |
| Fixed Interval | Responding may increase as the interval nears its end |
| Variable Interval | Moderate, relatively steady responding |
These are general patterns, not guarantees for every child.
Human behavior is affected by many variables beyond the schedule itself, including motivation, reinforcer quality, effort, past learning, competing activities, prompts, and the environment.
Behavior analysts therefore rely on individual data rather than assuming a particular reinforcement schedule will produce exactly the same response pattern for every learner.
Nurturing Nests’ guide to ABA behavior data sheets explains how therapists track responses and use those patterns to make treatment decisions.
When Are Ratio and Interval Schedules Used?
Ratio schedules and interval schedules organize reinforcement around different features of behavior.
A ratio schedule is based on how many qualifying responses occur. This can make sense when the treatment goal involves completing countable responses, such as answering questions, finishing practice items, or performing a specific task.
An interval schedule is based on when a qualifying response occurs after a certain amount of time has passed. This can be useful when reinforcement opportunities are meant to be distributed across time rather than tied to every few responses.
This does not mean ratio schedules are always better for task completion or interval schedules are always better for steady behavior. ABA therapists select schedules based on the target behavior, treatment goal, learner response, and practical setting.
How Are Reinforcement Schedules Used During Skill Acquisition?
New skills are often taught with frequent reinforcement so the connection between a correct response and its consequence is clear.
Consider a child learning to identify colors during discrete trial training.
The therapist says:
“Touch red.”
The child touches the red card.
The therapist immediately provides the planned reinforcement.
During early learning, each correct response may be reinforced. Once the child begins responding accurately and independently, the schedule can gradually change.
This transition does not mean reinforcement disappears.
Instead, reinforcement may become less frequent, more natural, or tied to a larger amount of responding.
The schedule should change according to progress rather than simply because a certain number of sessions have passed.
What Is Reinforcement Schedule Thinning?
Schedule thinning means gradually increasing the amount of responding or time required before programmed reinforcement is delivered.
A learner might move from:
CRF → FR 2 → FR 3 → FR 5
Or a time-based arrangement might gradually increase the interval between reinforcement opportunities.
The purpose is to help established behavior continue when programmed reinforcement becomes less frequent and to make the reinforcement plan more practical in everyday life.
Schedule thinning is not the same as reinforcement withdrawal. Thinning changes how often programmed reinforcement is available. Withdrawal means reinforcement is discontinued. In many ABA programs, natural consequences continue supporting useful behavior even as additional programmed reinforcers become less frequent.
Schedule thinning should usually happen gradually. Moving too quickly from frequent reinforcement to very limited reinforcement can reduce responding or make the task less motivating.
ABA therapists watch the target behavior during each change. If performance drops substantially, the schedule may need to be adjusted.
This is one reason reinforcement schedules work alongside other ABA therapy techniques rather than being selected in isolation.
What Are Compound Schedules of Reinforcement?
Compound schedules combine two or more basic schedules into a more complex arrangement.
Many ABA training materials group seven common forms:
- Concurrent
- Multiple
- Mixed
- Chained
- Tandem
- Alternative
- Conjunctive
These are more technical than the four basic schedules and are generally most relevant to ABA professionals and students studying behavior analysis.
Concurrent Schedules
A concurrent schedule makes two or more reinforcement options available at the same time for different responses.
For example, a learner might be able to choose between two activities that provide reinforcement according to different schedules.
Concurrent schedules are closely connected to the matching law, which describes how behavior may be distributed among available choices in relation to the reinforcement obtained from each option. Relative responding can approximate relative reinforcement rates across concurrently available choices.
Multiple and Mixed Schedules
A multiple schedule alternates between two or more reinforcement schedules, with a different cue signaling which schedule is currently in effect.
A mixed schedule also alternates between schedules, but the change is not signaled by a distinct cue.
The key difference is whether the learner has a stimulus indicating which reinforcement condition is active.
Chained and Tandem Schedules
A chained schedule requires two or more schedule components to occur in a particular sequence, with different cues signaling the components. Reinforcement typically follows completion of the final component.
A tandem schedule also requires components to occur in sequence, but distinct cues do not signal each component.
Alternative and Conjunctive Schedules
An alternative schedule provides reinforcement when either one of two schedule requirements is completed.
Think:
Requirement A OR Requirement B
A conjunctive schedule requires both requirements to be satisfied.
Think:
Requirement A AND Requirement B
These distinctions help behavior analysts describe reinforcement arrangements more precisely than a single FR, VR, FI, or VI schedule allows.
What Is the Matching Law in ABA?
The matching law helps explain choice when more than one source of reinforcement is available.
In simple terms, people may allocate more behavior toward options associated with relatively greater reinforcement.
Imagine a child can gain attention by appropriately requesting it, while another behavior also sometimes produces attention. The amount, quality, delay, and availability of reinforcement for each response can influence which behavior occurs more often.
The matching law is especially relevant to concurrent reinforcement schedules because more than one reinforcement option is available at the same time.
For ABA therapists, this highlights an important practical point: teaching an appropriate behavior may not be enough if a competing behavior continues to produce stronger or more frequent reinforcement.
Are DRA, DRI, DRO, DRL, and DRH Reinforcement Schedules?
DRA, DRI, DRO, DRL, and DRH are differential reinforcement procedures. They describe which patterns of behavior receive reinforcement rather than simply using the basic FR, VR, FI, or VI timing rules.
Common forms include:
- DRA: Differential Reinforcement of Alternative Behavior
- DRI: Differential Reinforcement of Incompatible Behavior
- DRO: Differential Reinforcement of Other Behavior
- DRL: Differential Reinforcement of Low Rates
- DRH: Differential Reinforcement of High Rates
For example, DRA reinforces an appropriate alternative behavior. If a child calls out to obtain help, a treatment plan might reinforce appropriately requesting assistance instead.
DRI reinforces a behavior that cannot occur at the same time as the target behavior, while DRO arranges reinforcement based on the absence of a specified behavior during a defined period.
They should not be confused with the four basic intermittent reinforcement schedules.
How Do Therapists Choose a Reinforcement Schedule?
There is no single reinforcement schedule that is best for every behavior.
A BCBA may consider:
- Whether the skill is new or already established
- How frequently the behavior should occur
- How much effort the response requires
- Which reinforcers are effective
- Whether reinforcement occurs naturally
- How the child responds when reinforcement becomes less frequent
- The environment where the behavior should eventually occur
A new communication response may benefit from frequent reinforcement.
A well-established skill may be ready for a thinner schedule or more natural consequences.
The schedule must also be practical. A reinforcement plan that works during a structured therapy session may need adjustments before it fits naturally into home, school, or community routines.
What Can Reinforcement Schedules Look Like at Home?
Parents may already use reinforcement schedules without labeling them as FR, VR, FI, or VI.
For example:
Continuous reinforcement: Your child receives enthusiastic praise each time they independently use a newly learned communication response.
Fixed ratio: A child earns a short preferred activity after completing three agreed-upon practice tasks.
Variable ratio: Praise or another planned reinforcer occurs after varying numbers of appropriate responses.
Variable interval: After varying periods have elapsed, the next qualifying occurrence of the target behavior may contact the planned reinforcement.
Parents should not create complicated reinforcement schedules simply because they know the terminology. The schedule should reflect the child’s treatment goals, current skills, and recommendations from the ABA team.
During in-home ABA therapy, families can learn how reinforcement fits into daily routines, how reinforcement schedules may change as skills improve, and how natural consequences can gradually take a larger role.
Conclusion
Reinforcement schedules in ABA help determine when and how often desired behaviors contact reinforcement as children learn and strengthen new skills. Continuous reinforcement can provide frequent feedback during early learning, while fixed ratio, variable ratio, fixed interval, and variable interval schedules offer different ways to make programmed reinforcement less frequent as behavior becomes established. More advanced arrangements, including concurrent and other compound schedules, help behavior analysts describe complex reinforcement patterns. The goal is not to choose the most technical schedule, but to select and adjust reinforcement according to the child’s behavior, progress, treatment goals, and everyday environment.
At Nurturing Nests Therapy Center, Inc., our Board Certified Behavior Analysts and Behavior Technicians use individualized ABA strategies to support communication, learning, daily routines, and greater independence for children throughout Los Angeles and the San Fernando Valley. Treatment decisions are guided by each child’s progress rather than a one-size-fits-all reinforcement plan. Contact us to learn more about personalized ABA support for your family.
FAQs
What are the four schedules of reinforcement?
The four basic intermittent schedules of reinforcement are fixed ratio, variable ratio, fixed interval, and variable interval. Fixed ratio and variable ratio schedules are based on the number of responses, while fixed interval and variable interval schedules are based on time. Fixed schedules use predictable requirements, while variable schedules change around an average.
What is a reinforcement schedule in ABA?
A reinforcement schedule in ABA is a rule that determines when a target behavior receives reinforcement. A behavior may be reinforced every time it occurs through continuous reinforcement or intermittently according to a response-based or time-based schedule. ABA therapists adjust these schedules based on skill acquisition, current performance, and treatment goals.
What are the 7 compound schedules of reinforcement in the ABA curriculum?
Many ABA training materials group seven common compound schedules: concurrent, multiple, mixed, chained, tandem, alternative, and conjunctive schedules. Concurrent schedules make different options available at the same time; multiple and mixed schedules alternate components; chained and tandem schedules arrange components sequentially; and alternative and conjunctive schedules combine requirements using either-or or both-required rules.
What are DRO, DRI, DRA, DRL, and DRH all examples of?
DRO, DRI, DRA, DRL, and DRH are all differential reinforcement procedures. DRA reinforces an alternative behavior, DRI reinforces an incompatible behavior, DRO reinforces the absence of a target behavior, DRL reinforces lower rates of behavior, and DRH reinforces higher rates. These procedures determine which behavior pattern earns reinforcement and are different from the four basic fixed and variable reinforcement schedules.
