What Are the 2 Main Functions of Behavior in ABA?

• October 16, 2025
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Have you ever wondered why a particular behavior happens? In Applied Behavior Analysis (ABA), we look for the “why” behind the action. This “why” is known as the function of a behavior. Understanding the purpose a behavior serves is the most critical step in creating a plan to support positive change. Instead of just looking at the behavior itself, behavior analysis allows us to understand the motivation behind it, which is the key to helping individuals learn and grow in meaningful ways.

Foundations of Applied Behavior Analysis (ABA)

Applied Behavior Analysis (ABA) is a science-based approach focused on understanding and improving behavior. Through ABA therapy, we can help individuals develop new skills and reduce behaviors that may be challenging. The core of this approach is objective measurement and analysis.

Effective behavior management in ABA isn’t about guesswork; it’s about systemically finding what works for each person. This scientific method helps us create creative interventions that lead to real progress, we will explore the core principles of ABA and how behaviors are classified.

Core Principles of ABA Therapy

The foundation of ABA therapy rests on several core principles, with positive reinforcement being one of the most well-known. This principle involves encouraging positive behaviors by offering a rewarding consequence immediately after the desired action occurs. For example, offering praise when a child makes eye contact can increase the chance they will do it again.

A certified behavior analyst uses the principles to create individualized plans. The process begins with identifying behavior functions—the reasons behind a person’s actions. Is the behavior meant to gain something, or is it intended to avoid something? Answering this question is the first step.

Once the function is understood, the analyst can design an intervention. Instead of reacting to a behavior, ABA therapy proactively teaches an alternative, more appropriate behavior that achieves the same goal. The approach empowers individuals by giving them better tools to communicate and interact with their world.

How ABA Approaches Human Behavior

ABA therapy takes a systematic and analytical approach to human behavior. It operates on the idea that behavior is learned and that it serves a purpose. Rather than simply labelling a behavior as “good” or “bad,” behavior analysis seeks to understand what triggers the behavior and what happens afterwards that makes it continue.

This is often called the ABA model: Antecedent (what happens right before), Behavior (the action itself), and Consequence (what happens right after). By observing and analyzing these three components, therapists can uncover the function behind a challenging behavior. This method provides a clear framework for effective behavior management.

Understanding this pattern is everything. It shifts the focus from just stopping a challenging behavior to teaching a more functional skill that meets the same underlying need. This supportive approach helps individuals learn new, positive ways to navigate their environment and get their needs met appropriately.

Classifications of Behavior in ABA

In Applied Behavior Analysis, behaviors are not random; they are classified based on their purpose or function. While motivations can seem complex, they are often simplified into two main categories. This classification is the cornerstone of developing an effective plan, as the strategy must match the reason for the specific behavior.

Understanding these behavioral functions helps therapists target the root cause rather than just the symptom. If an intervention does not align with the behavior’s function, it is unlikely to lead to lasting, positive change. The primary goal is to teach a replacement skill that serves the exact same purpose in a more acceptable way.

All behaviors can essentially be sorted into two primary groups: actions taken to gain something desired or actions taken to get away from something undesired.

Function Category	Purpose of the Behavior
Access	To gain or obtain something, such as attention, a tangible item, or a preferred activity.
Escape	To avoid, delay, or get away from something, like a non-preferred task, a loud noise, or a social demand.

Understanding Behavior Functions in ABA

The concept of a “function of behavior” is central to Applied Behavior Analysis. It simply refers to the reason or purpose behind an action. Every behavior, from the simplest to the most complex, happens for a reason. In ABA, we focus on identifying that reason to create truly effective interventions.

Instead of just trying to stop a behavior, understanding its function allows us to teach a better way to achieve the same result. Let’s look closer at what a function is, why it’s so important to identify, and how it guides our strategies.

What Is a Function of Behavior?

The function of a behavior is the underlying reason why it occurs. Think of it as the motivation driving the action. In ABA therapy, we don’t just look at what the behavior looks like on the surface; we investigate what the person gets out of it. This is the key to understanding and influencing socially significant behaviors.

For example, a child might cry. The behavior is crying, but the function could be to get a hug (accessing attention) or to avoid having to put toys away (escaping a demand). The behavior is the same, but the underlying reason is completely different.

By focusing on the “why,” ABA shifts the perspective from merely managing a problem to solving a communication challenge. The behavior is a message, and our job is to figure out what that message is. This understanding is what allows us to teach more appropriate ways for a person to express their needs.

Why Identifying Function Matters in ABA

Identifying the function of behavior is arguably the most critical part of ABA therapy. Without knowing why a behavior is happening, any attempt to change it is just a guess. It’s like trying to fix a leaky pipe without knowing where the leak is coming from. You might clean up the water, but the problem will persist.

This understanding is what leads to lasting, positive behavior change. When intervention strategies are function-based, they are tailored to the individual’s specific needs and motivations. This creates a more compassionate and effective approach that empowers the individual.

Here’s why it matters so much:

• It ensures interventions address the root cause, not just the symptom.
• It helps therapists teach a replacement behavior that works for the individual.
• It prevents the use of ineffective or mismatched strategies that could make things worse.

How Functions Guide Effective Interventions

Once behavior analysis reveals the function of a behavior, it becomes the roadmap for creating effective interventions. The entire strategy is built around this core piece of information. The goal is no longer to just stop an action but to teach a new skill that serves the same purpose in a more appropriate way.

For instance, if a child’s behavior is driven by a desire to access a toy, the intervention won’t focus on punishment. Instead, the intervention strategy will focus on teaching the child how to ask for the toy. The therapist would then use positive reinforcement, like praise and giving the toy, when the child uses the new skill.

This function-based approach ensures that the person’s needs are still met. It validates their motivation while providing a better, more effective way to communicate it. This method honors the individual and builds skills, leading to more meaningful and independent participation in their daily lives.

Two Main Functions of Behavior in ABA Explained

All behaviors can typically be traced back to one of two primary motivations. These are the two main functions of behavior in ABA: to get something or to get away from something. We refer to these as the access function and the escape function. Understanding these core drivers is essential.

Every behavior serves one of these purposes. Grasping the distinction between these two behavior functions is the first step toward developing a targeted and successful intervention. Let’s explore what each function looks like and how they differ from one another.

The Access Function: Seeking Positive Outcomes

The access function is all about trying to obtain something desirable. When a behavior is driven by access, the individual is trying to get attention, a specific item, or a favorite activity. This is reinforced by getting what they want, which is a form of positive reinforcement.

This can happen in various ways. A child might pull on your sleeve to get your attention, or they might cry at the store to get a piece of candy. The behavior is a tool they are using to gain access to something they value. The goal of ABA is to teach new skills to access these things in more appropriate ways.

Examples of access-motivated behaviors include:

• Engaging in disruptive actions to get a reaction from peers or adults.
• Pointing or grabbing to get tangible items like a toy or a snack.
• Asking to play a game to start a preferred activity.

The Escape Function: Avoiding or Delaying Unwanted Events

On the other side is the escape function. Escape behaviors are used to avoid, delay, or get out of a situation the person finds unpleasant. This could be a difficult task, a loud environment, or an unwanted social interaction. When the behavior successfully removes the unwanted event, it’s strengthened through negative reinforcement.

For example, a student might act out in class to get sent to the principal’s office, thereby escaping a difficult math lesson. An individual might cover their ears and hum loudly to block out overwhelming sensory needs. These actions serve the purpose of providing relief from a stressor.

Common escape-driven behaviors include:

• Refusing to do homework or chores to avoid the task.
• Running away from a group activity to escape social demands.
• Engaging in problem behaviors when a non-preferred food is presented.

Key Differences Between Access and Escape Functions

The simplest way to understand the difference between the access function and the escape function is to think about “getting” versus “getting away.” The function of behavior is determined by its outcome. Does the behavior result in gaining something or removing something?

The access function is about addition. The individual’s behavior adds something positive to their environment, like attention or a favorite toy. The escape function is about subtraction. The behavior removes something negative from their environment, like a difficult task or an unpleasant sensory experience.

Understanding this distinction is vital because the intervention for each is completely different. Here are the key differences:

• Goal: Access seeks to obtain something desirable; Escape seeks to avoid something undesirable.
• Reinforcement: Access is maintained by positive reinforcement (getting a reward); Escape is maintained by negative reinforcement (removing a stressor).
• Motivation: The motivation for access is a want or desire; the motivation for escape is an aversion or dislike.

Identifying the Function of Behavior in Practice

Determining the function of behavior isn’t a guessing game. ABA therapists use a systematic process to pinpoint why a behavior is occurring. This involves careful observation, precise data collection, and in-depth behavior analysis to form a clear hypothesis about the behavior’s purpose.

This methodical approach ensures that the resulting plan is based on evidence, not assumptions. The following sections will detail the techniques used, including the formal process of a functional analysis, to accurately identify the function.

Observation Techniques and Data Collection

The first step in understanding a behavior is watching it happen. ABA therapists use direct observation to gather information in the person’s natural environment. They don’t just look at the behavior itself; they record what happens right before it (the antecedent) and right after it (the consequence).

This systematic data collection is crucial. Therapists use specific tools and methods to track the behavior’s frequency, duration, and context. Over time, this data reveals patterns that point toward one of the behavior functions. Is the behavior more likely to happen when a demand is placed or when the child is alone?

Key observation techniques include:

• ABC Data: Recording the Antecedent, Behavior, and Consequence for each occurrence.
• Scatterplot Analysis: Noting when and where a behavior occurs to identify patterns related to time or setting.
• Interviews: Talking to parents, teachers, and caregivers to gather insights about the behavior in different settings.

Conducting a Functional Behavior Assessment (FBA)

A Functional Behavior Assessment (FBA) is the formal process used to identify the purpose behind problem behaviors. It’s a multi-step investigation conducted by a certified behavior analyst that synthesizes information from various sources to form a hypothesis about the function.

The FBA goes beyond simple observation. It includes reviewing records, interviewing caregivers, and analyzing the ABC data collected. The goal is to get a complete picture of the behavior and the environmental factors that might be influencing it. This assessment is the foundation of any effective behavior intervention plan.

In some cases, if the function is still unclear, the analyst may proceed with a functional analysis. This involves systematically testing the hypothesized behavior functions in a controlled way to confirm which one is driving the behavior. This ensures the chosen intervention is precisely targeted to the correct motivation.

Role of Behavior Analysts in Determining Function

Behavior analysts are the experts who lead the process of determining the function of behavior. Their specialized training equips them to conduct FBAs, interpret data, and design effective ABA therapy services. They have the clinical judgment needed to see the patterns that might not be obvious to an untrained eye.

The analyst’s role is to act as a detective, piecing together clues from observations, interviews, and data to solve the puzzle of the behavior. They understand the nuances that differentiate the functions and can design interventions that address a child’s unique needs.

Ultimately, the behavior analyst is responsible for creating a comprehensive plan that not only addresses the challenging behavior but also teaches a more functional replacement skill. They collaborate closely with families and other therapists to ensure the plan is implemented consistently and effectively, paving the way for meaningful progress.

Everyday Examples of Access and Escape Behaviors

The access function and escape function are not just clinical terms; they are at play in our lives every single day. Once you know what to look for, you’ll start to see these motivations behind the actions of children and adults all around you. These real-life examples can make the concepts much clearer.

Behavior analysis helps us decode everyday actions. Let’s look at some common examples of behaviors motivated by access and escape that you might see at home, at school, or out in the community.

Real-Life Access-Motivated Behaviors in Children and Adults

Behaviors driven by the access function are all about getting to positive outcomes. This can be as simple as a baby crying to be picked up or as complex as an adult working extra hours to get a promotion. The goal is always to obtain something desirable.

In children, this is very common. A toddler might have a tantrum in the toy aisle because, in the past, it resulted in getting a new toy. A student might tell a joke in class to gain social interaction and laughter from their friends. The behavior is a strategy to achieve a specific goal.

Here are some everyday examples:

• A child repeatedly saying “Look at me!” while jumping on the couch to get a parent’s attention.
• An employee offering to help a coworker to build a good relationship (accessing social approval).
• A teenager asking for the car keys to gain access to a preferred activity with friends.

Common Escape-Driven Behaviors at Home and School

Escape-driven behaviors are actions we use as coping mechanisms to get away from something we find unpleasant, or an aversive stimulus. These are just as common in daily life as access-motivated behaviors.

At home, you might see a child who suddenly says their stomach hurts when it’s time to do chores. At school, a student might start doodling or looking out the window when a difficult subject is being taught. These behaviors, whether conscious or not, serve to delay or remove the unwanted task.

Here are a few more examples:

• A person leaving a loud party early to escape overwhelming sensory stimulation.
• A child sliding out of their chair and hiding under the table when dinner includes vegetables they dislike.
• A teenager saying “I’ll do it later” to postpone taking out the trash.

How to Recognize the Function Behind Everyday Actions

Recognizing the function of behavior in the moment can help you respond more effectively. The key is to use a simplified form of behavior analysis and ask yourself: What happened right before, and what happened right after? This can help you better understand the root cause.

Through direct observation, pay attention to the context. If your child acts out every time you ask them to do homework, the function is likely escape. If they act out when you are on the phone, the function is likely access to your attention. The trigger and the result are your biggest clues.

To figure it out, ask yourself these questions:

• What did the person get or get out of by doing this? (This points to the consequence).
• Was something unpleasant removed, or was something pleasant gained?
• What was happening right before the behavior started? (This points to the antecedent).

Strategies for Addressing Access and Escape Functions in ABA

Once the function of a behavior is known, we can select from a range of evidence-based ABA techniques to promote positive behavior change. The chosen intervention strategies will be completely different for a behavior driven by access versus one driven by escape. Effective behavior management is about teaching, not just reacting.

The goal is always to give the individual a more appropriate and effective way to get their needs met. Let’s explore some of the specific strategies used for both access-motivated and escape-motivated behaviors.

Intervention Techniques for Access-Motivated Behaviors

For behaviors with an access function, intervention strategies focus on teaching the person appropriate ways to request what they want. This involves identifying effective replacement behaviors and using positive reinforcement to strengthen them. The key is to make the new, appropriate behavior more efficient at getting the desired outcome than the old, challenging behavior was.

For example, a child who used to grab toys is taught to say, “My turn, please.” When they use this phrase, they are immediately given the toy and praised. This teaches them that a polite request works better than grabbing.

Common intervention techniques include:

• Functional Communication Training (FCT): Teaching a specific phrase, sign, or gesture to ask for an item or attention.
• Differential Reinforcement: Providing reinforcement only when the replacement behavior occurs and withholding it for the problem behavior.
• Waiting Programs: Teaching the skill of waiting patiently after making a request.

Evidence-Based Approaches for Managing Escape Behaviors

When managing escape behaviors, the goal is to make the unwanted task more tolerable and teach appropriate ways to ask for a break. Effective strategies within an ABA program often involve modifying the task or environment to reduce the person’s motivation to escape in the first place.

For instance, if a child tries to run away from a worksheet, the therapist might break the worksheet into smaller, less overwhelming parts. They would also teach the child to say, “Break, please,” and honor that request. This gives the child control and a functional way to cope.

Evidence-based approaches include:

• Task Modification: Making a task shorter, easier, or more interesting.
• Choice-Making: Offering choices within the task, such as “Do you want to do math or reading first?”
• Non-contingent Reinforcement: Providing frequent, scheduled breaks that are not dependent on the problem behavior.

Teaching Functional Communication as a Replacement Strategy

One of the most powerful strategies in ABA is teaching Functional Communication Training (FCT). This involves identifying the function of a behavior and teaching a specific communicative act that serves the same purpose. These replacement behaviors give individuals appropriate ways to express their needs.

Whether the function is access or escape, FCT provides a concrete skill. A child who screams for attention is taught to tap someone’s shoulder and say “excuse me.” A student who rips up papers to avoid work is taught to hand over a “break” card. FCT directly replaces a problem with a solution.

This strategy is highly effective because it:

• Directly addresses the underlying motivation of the behavior.
• Builds crucial communication and social skills.
• Empowers individuals by giving them a voice to express their wants and needs.

Conclusion

In conclusion, understanding the two main functions of behavior—access and escape—is essential in Applied Behavior Analysis (ABA) for effective intervention strategies. By identifying whether a behavior is driven by a desire to gain something positive or to avoid an unwanted situation, therapists can tailor their approaches to better support individuals. This knowledge not only enhances the effectiveness of interventions but also promotes meaningful progress in therapy. As you navigate the world of ABA, remember that recognizing these behavior functions is key to achieving more successful outcomes. If you’re ready to dive deeper into ABA therapy or need assistance, don’t hesitate to reach out for a consultation!

At Kids N Heart ABA, we believe that understanding behavior is the key to unlocking meaningful progress. Serving families across North Carolina, our expert team uses compassionate, evidence-based ABA strategies to uncover the “why” behind every action—helping children communicate, learn, and grow with confidence. We focus on building positive behaviors that last, empowering each child to thrive in school, at home, and beyond. With Kids N Heart ABA, families experience more than therapy—they discover a true partner in their child’s journey toward independence, connection, and lasting success.

FAQs

Are there other recognized functions of behavior in ABA besides access and escape?

Yes, while access and escape are the two broadest categories, behavior analysis often breaks them down further. The access function can be split into gaining social interaction (attention) and obtaining tangible items. A third major function is automatic reinforcement, often related to sensory stimulation, where the behavior itself feels good.

How do therapists accurately determine the function of a child’s behavior in ABA?

Behavior analysts use a process called a Functional Behavior Assessment (FBA). This involves direct observation, interviews, and data collection to form a hypothesis. For complex cases, they may conduct a functional analysis, systematically testing conditions to confirm the behavior’s purpose, which is essential for creating effective treatment plans.

How does understanding the main functions of behavior improve ABA therapy outcomes?

Understanding the function allows for effective treatment that targets the root cause of a behavior, not just the symptom. This ensures the ABA therapy plan meets the child’s unique needs, teaches appropriate behaviors that serve the same purpose, and leads to more meaningful and lasting positive behavior change.

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Sources:

• https://www.autismspeaks.org/applied-behavior-analysis
• https://www.simplypsychology.org/positive-reinforcement.html
• https://raisingchildren.net.au/autism/behaviour/understanding-behaviour/positive-behaviour-autistic-children-teenagers
• https://www.understood.org/en/articles/functional-behavioral-assessment-what-it-is-and-how-it-works
• https://www.appliedbehavioranalysisedu.org/how-is-functional-communication-training-used-in-applied-behavior-analysis/