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High-Probability Request Sequences & Behavioral Momentum: A Deep Dive for ABA Professionals


As professionals in ABA, we’re constantly seeking ways to maximize the effectiveness of our interventions. One strategy that’s proven to be highly effective is the use of high-probability request sequences and behavioral momentum.

This post will explore these concepts, their applications, and their benefits in ABA therapy.

What are High-Probability Request Sequences?

High-probability (high-p) request sequences present a series of requests with which the individual has a high likelihood of completing, followed by a low-probability (low-p) request or a request with which they are less likely to do.

The theory behind this strategy is that motivation with the high-p requests builds “momentum,” which makes it more likely the individual will be motivated for the subsequent low-p request.

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In practical terms, asking a child to perform easy, mastered tasks (like touching their nose or clapping their hands) before presenting a more difficult request (like putting on their coat) is an example of behavioral momentum. Giving a busy person just one more task to complete after they’ve completed a series of other tasks is also considered momentum.

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What is Behavioral Momentum?

Behavioral Momentum in ABA is a concept that describes the persistence of behavior even after conditions have changed. It’s similar to the principle of momentum in physics but applied to behavior.

In practice, a behavior performed consistently and rapidly, often in response to high-probability requests, tends to continue even when faced with low-probability requests or disruptions. This momentum can be harnessed beneficially in therapeutic settings to encourage motivation with less preferred tasks or requests.

Benefits of High-P Request Sequences & Behavioral Momentum

Using high-p request sequences and leveraging behavioral momentum can have several advantages in an ABA setting:

  • Increased Motivation: The primary advantage of this strategy is increased instructional motivation with low-p requests. This can be particularly useful in teaching new skills or managing challenging behaviors.
  • Improved Learning Environment: High-p request sequences contribute to a more positive learning environment by increasing the rate of reinforcement and success, which can improve motivation and engagement.
  • Versatility: These techniques can be applied across various behaviors and settings, making them versatile tools for ABA professionals.


High-P Request Sequence Strategy

Let’s break down the steps to implementing this strategy effectively:

1. Identify High-Probability Requests

Begin by creating a list of high-probability requests that your learner can complete independently and without hesitation 100% of the time. These could be gross motor imitation drills (e.g., “Do this” while you clap your hands), following one-step instructions (e.g., “Stomp your feet”), or even verbal responses (e.g., “What’s your name?” “How old are you?” “What’s this?” “Say ___”).

2. Sequence the Requests

Once you have your list, use these high-probability requests in a sequence. Present 2 to 5 requests quickly to the learner before introducing the low-probability request. We often have a stack of cue cards on the table or high-p instructions written on a whiteboard for exactly this purpose.

3. Implement Differential Reinforcement

Different reinforcement must be used while implementing a high-probability request sequence. For example, verbally praise each high-p response that is followed (or every few high-p responses), but then really praise or provide a tangible when the learner engages in the low-probability response.

4. Reinforce Low-Probability Requests

When the learner completes a low-probability request, reinforce this immediately with a powerful reinforcer (such as a preferred item or activity).

5. Incorporate into Sessions

As you run instructional programs with your learners, integrate the high-probability request sequence at the beginning and throughout the session. This strategy helps reduce the occurrence of challenging behaviors.

6. Implement the Sequence with Low-Probability Tasks

Once a task is identified as a low-probability request (i.e., the client engages in escape-related behaviors), predict those challenging behaviors before teaching and implement the high-probability request sequence first!

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Example of a High-Probability Request Sequence

The learner consistently engages in escape-related or tantrum behaviors while practicing for their spelling test.


Type of Request SD Response Reinforcer
High-P Request 1 “Write your name” Student writes name “Great job!”
High-P Request 2 “Write the date” Student writes date “Excellent work!”
High-P Request 3 “Underline the first word” Student underlines first word “Amazing!”
Low-P Request “Copy the first word” Student copies first word “Wow! Here is a sticker!”


Implementing High-P Request Sequences & Behavioral Momentum in Your ABA Practice

When implementing high-p request sequences, it’s essential to ensure that the high-p requests are truly high-probability. They should be tasks that the individual almost always completes. Also, the transition to the low-p request should be smooth and quick to maintain the momentum.

Regarding behavioral momentum, it’s crucial to identify and consistently reinforce the target behavior to increase its resistance to change. Gradually introducing challenges or distractions can help strengthen the behavior further.

Important Reminders for Effective High-P Request Sequences & Behavioral Momentum

As we conclude, it’s crucial to remember some key considerations that can significantly impact the effectiveness of high-p request sequences and behavioral momentum in your ABA practice.

Seamless Instruction Flow

Maintain an uninterrupted flow between instructions. Go quick. The aim of the high-p request sequence is to harness the behavioral momentum created by the high-p requests. Any breaks can disrupt this momentum, reducing the likelihood of success with the low-p request.

Mindful Timing

If a learner exhibits problem behaviors, hold off on using the high-p request sequence immediately. We want to prevent the client from associating these behaviors with gaining access to easier requests.

Balanced Request Distribution

Don’t limit your instruction to high-p requests only. While it might be tempting to avoid escape-related behaviors associated with low-p requests – such as aggression or self-injury – it’s essential to challenge your clients based on their abilities. Be aware of your learners’ needs and prepare for challenging behaviors, but don’t shy away from low-p requests.

Consistent Follow-Through

Ensure you’re following through with your instructions. This helps maintain consistency and reinforces the importance of instructional motivation. For more on this, check out our post on Following Through.

Remember, as ABA professionals, our goal is to guide our learners toward progress, even when faced with challenges. By using high-probability request sequences and leveraging behavioral momentum effectively, we can make a significant difference in their lives.

High-probability request sequences and behavioral momentum are powerful strategies in the ABA professional’s set of tools. By understanding and effectively applying these strategies, we can enhance the effectiveness of our interventions and promote positive behavior change.




4 thoughts on “High-Probability Request Sequences & Behavioral Momentum: A Deep Dive for ABA Professionals”

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