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Functions of Behavior in ABA: Complete Guide

ABA uses the functions of behavior to understand behavior and why it occurs. When you accurately identify the function of a behavior, you answer the question: What does this person “get” out of engaging in this behavior. This answer allows you to select function-based interventions to address the behavior.

All behavior occurs because the individual gets something out of it.  In Applied Behavior Analysis (ABA), the reason a behavior continues is called the function of that behavior. These functions are reinforcers for the child.  If the behavior no longer works for that purpose, the behavior will stop and a new behavior will take its place.

In this article we will use examples related to challenging behavior; however, the information here can be applied to teaching new skills. Once the appropriate function of a child’s behavior has been identified, you can use this information to identify potential reinforcers for more appropriate behaviors.

The examples in this article are available in this free download for your reference:


Functions of Behavior Access and Escape in Action How Many Functions Are There, Really? Try it for Yourself

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Functions of Behavior

Accurately identifying function allows you to make informed decisions to change behavior. Understanding why a behavior occurs leads to meaningful change. You can then use this information to alter the conditions surrounding the behavior.

While there are many factors that motivate behavior, there are 2 primary functions of behavior that make a behavior more likely to happen in the future:

  • Access 
  • Escape 

Looking further at these primary functions, you can dig a little deeper to determine if the reinfocer is received directly or is socially mediated (provided by someone else). Knowing how the individual accesses the reinforcer assists you in determining how best to change the behavior.

Start with this quick overview and see below for more detail:

Access Maintained Behaviors

Many behaviors occur because the individual gains access to something that is of value to them.  The individual can gain access to a variety of different reinforcers including:

  • Something tangible
  • An activity
  • A sensory experience
  • Attention

Access to Tangibles

A tangible is something the person can touch or pick up. It could be anything from a toy to a piece of candy or even something that appears uninteresting to you. Young children with autism often develop intense interests in items that appear random such as flags, straws or pipes.

Access to Activities

Many children are motivated by activities that they find enjoyable. Does your client enjoy any of the following?

  • Bubbles
  • Tickles
  • TV
  • Music

Access to these activities may reinforce behavior. Other activities may also reinforce a behavior without you being aware of it.

Access to a Sensory Experience

Another type of activity that your client might find reinforcing is stereotype. This might look like hand flapping, arm waving, hand tapping or finger wiggling. These types of behaviors, often referred to as “nonfunctional,” feel good to the individual. In this case, “nonfunctional” means that they don’t serve a useful purpose. Stereotypies are often considered in their own category of function of behavior called Automatic Reinforcement. For the purposes of this article, we will include them in the Access category and discuss their counterpart: escape from a sensory experience. Although some children with autism avoid extraneous sensory input, many seek sensory input from a variety of activities.

Access to Attention

Attention and social interactions reinforce many behaviors. Some children have positive reactions when an adult delivers praise or even provides a reprimand. Inappropriate behaviors can be unintentionally reinforced by attention such as reprimands if the learner is reinforced by access to attention.

Modes of Accessing a Reinforcer

Once you determine if a behavior is maintained by access, you can look deeper to determine how the individual is gaining access to the reinforcer. There are 2 ways that the individual gains access to the reinforcer:

  • Direct access
  • Socially mediated access

Direct Access

Many times individuals are able to directly access a reinforcer without the help of another individual. The child who takes a toy out of the hands of a peer has gotten direct access to the toy. The child who runs to the swing on the playground and swings on his belly has direct access to that activity. When a child spins in circles, she has access to that sensory experience.

While direct access is easy to understand, it may be difficult to prevent. A child who struggles with overeating but knows how to get into the refrigerator and cabinet can directly access food unless his parents find a way to block this behavior or teach an alternative.

Socially Mediated Access

Socially mediated access requires a bit deeper look. This mode provides access to the reinforcer through another person. Whether that access is granted intentionally or inadvertently, the other person is necessary for the individual to gain access to the tangible, activity, sensory experience or attention. Why would anyone reinforce a challenging behavior by giving access to a reinforcer? Often the person mediating (providing) the access is not aware of the potential consequences. It may also be that the benefits for that person are greater than the perceived risk of granting access.

Socially mediated access to a tangible

Often socially mediated access to a tangible reinforces challenging behavior because the adult didn’t anticipate a problem developing by allowing access to that tangible. Here’s an example:

Jim enjoys small fidget toys, especially ones that are squishy. Jim often struggles during group activities where there are no hands-on activities such as circle time or story time. The OT recommends watching his behavior and once he shows signs of distress (calling out, increased motor movement, crying), the teacher should give him a fidget toy to help him remain part of the group. Over time, Jim starts showing signs of distress earlier in circle and story time and he has begun to display these behaviors during other times as well.

In this example, the OT had good intentions. However, she did not consider the unintended effects of waiting for Jim to engage in problematic behavior before giving him access to the fidgets. Jim’s teacher was unaware that she inadvertently reinforced this behavior until it started to become a problem.

At times, nearly all parents have been guilty of “giving in” in order to make a behavior stop or to head off an impending explosion. When working with parents, it’s essential to remember that it’s unrealistic to expect that parents will never do this. Help parents identify the situations where they need to be consistent and where they might choose to “pick their battles” and let things slide a little.

Socially mediated access to activities

Many of the activities listed above motivate both desired and undesired behaviors depending on the context within which the child has gained access to the activities in the past. In much the same way as socially mediated access to a tangible occurs without intentionally reinforcing maladaptive behavior, socially mediated access to activities develops along a similar path. Here’s an example:

Tara’s mother can always tell when she’s getting “amped up” because she starts yelling at her brother and taking toys away from him. In order to avoid a massive meltdown, Tara’s mother turns on the TV as soon as Tara starts these behaviors. Over time, Tara’s mother has noticed that Tara is becoming “amped up” more often and she’s not sure what to do about it.

Socially mediated access to a sensory experience

While many sensory experiences don’t require another person in order to gain access, some do. Some children like deep pressure in the form of head squeezes, tight hugs or even tight fitting clothing. Other sensory experiences might include running fingernails along an arm or being spun on a swing. Take a look at this example:

Jennifer often has dramatic tantrums that include self-injurious behavior (SIB) and aggression. It’s difficult for her parents to identify what triggers these tantrums and they have become afraid of them as she has gotten bigger. They have found that providing deep pressure in the form of head and hand squeezes usually calms her. Each time she escalates, they begin to provide that pressure and they will often take turns when one gets tired.

Socially mediated access to attention

Attention always requires social mediation, but it is a powerful reinforcer. Many parents, caregivers and professionals feel the need to “correct” challenging behavior. They may feel that the child won’t learn that the behavior is undesirable unless they tell the child every time it occurs. Often adults feel as though they are letting the child “get away with” the behavior by not doing something to address it.

Many traditional parenting techniques require the parent to provide an extensive amount of attention contingent on problem behavior. Think about this example:

Jaime often throws toys when her parents ask her to clean up. Her parents have read many parenting books that recommend consistent consequences when challenging behaviors occur and they have decided to try “time out.” From what they read, Jaime should receive 1 minute of “time out” for each year of her age. Since she’s 5, she should be in “time out” for 5 minutes. They have chosen their “time out” spot, a hard chair in the corner of the living room.

The next time Jaime throws toys, her parents direct her to “time out.” She gets up repeatedly and her parents have to redirect her back to the chair. Finally, not knowing how else to keep her in “time out,” her mother sits in the time out chair with Jaime on her lap and holds her there for the full 5 minutes.

Escape Maintained Behaviors

Escape from something aversive can be a powerful motivator. Individuals will go to great lengths to escape or avoid things that are unpleasant such as:

  • A relatively lengthy task
  • A relatively difficult task
  • Unpleasant sensory experience
  • Attention or social interaction

Escape from a Relatively Lengthy Task

Some children find tasks that take a long time aversive. What constitutes a long time varies by the individual. One child might think that sitting at a table for 5 minutes is a long time. Another finds sitting for 30 seconds aversive. The aversiveness of the task is specific to the perspective of the individual. Even though you might feel as though it’s a quick task, the child might feel that it will take an unachievable amount of time.

Escape from a Relatively Difficult Task

For some children, it’s not how long the task will take but how difficult they expect the task to be. Again, this is specific to the child’s perception of the task, not how easy or difficult you think the task is for the child.

Escape from an Unpleasant Sensory Experience

While some children seek sensory experiences, many find specific sensations highly aversive. Unexpected loud noises, strobe lights, light touches or strong smells might appeal to one child and be aversive to another. A scent or sound you find pleasant might trigger a strong reaction from your client.

Escape from Attention or Social Interaction

Attention and social interactions reinforce many behaviors; however, for some children, these are aversive experiences. Some children have strong negative reactions when an adult delivers praise or provides a reprimand. Others engage in behaviors to avoid social interactions because socializing with others is an unpleasant experience.

Modes of Escape

As with access maintained behaviors, escape maintained behaviors can be either:

  • Direct escape
  • Socially mediated escape

Direct Escape

As with direct access, direct escape is pretty straightforward. Direct escape involves the individual being able to escape without the help of another person. A child who walks away from the dinner table escapes having to sit at the table for the whole duration of mealtime. The child who rips up her math homework escapes completing this difficult task. When a child covers his ears when the hand dryer starts in the public restroom, he directly escapes the sound of the dryer. Hiding under a blanket when someone walks into the room effectively escapes that social interaction.

Socially Mediated Escape

Socially mediated escape maintained behaviors are a bit more complex than direct escape maintained behaviors because they require the assistance of another person. As with socially mediated access maintained behaviors, undesired behaviors are often inadvertently reinforced by the adult for a variety of reasons.

Socially mediated escape from a relatively lengthy task

When an adult presents a lengthy task and subsequently allows the child to complete only a portion of the task or even escape the task altogether in response to the child’s objections, the child’s behavior is reinforced. Take a look at this example:

Kevin has been playing in his room for the last hour and has strewn trains, cars and blocks all over his room. Kevin’s mother comes in and tells him to clean up. Kevin begins to kick his legs, cry and throw toys. Kevin’s mother knows that the mess might seem overwhelming to him so she begins to help him clean up. When there are only a few blocks left to pick up, she has him complete the task. Kevin has successfully used his behavior to reduce the length this task will take. Understanding this contingency, you can begin to teach Kevin to use language (functional communication training) to reduce the length of the task. Teach Kevin to say “can you help me clean up?” rather than using maladaptive behavior.

Socially mediated escape from a relatively difficult task

Socially mediated escape from a relatively difficult task is similar to the above condition except another person is required to reduce the difficulty of the task or to escape the task altogether. Everyone likes to feel successful and when faced with a task that appears too difficult, challenging behavior can emerge. Consider this example:

Katie hates doing homework, especially reading because she has a hard time sounding out the words in new books. Her father does homework with her every night. Katie screams and cries through the process and repeatedly says she can’t do it. Usually the book ends up on the floor. Her father feels bad that she’s struggling and speaks to her teacher about reducing her homework. The teacher says that for homework Katie can read familiar books rather than the new ones she has been sending home with her. Katie’s father has helped her escape the task of reading new books for homework. Katie will be more likely to engage in these behaviors in the future when she is faced with difficult tasks.

Socially mediated escape from an unpleasant sensory experience

Many children will engage in serious maladaptive behavior in order to escape from an unpleasant sensory experience. Especially for young children, this behavior often requires the help of another person making this a socially mediated escape maintained behavior. Look at the following example:

The automatic hand dryers in public restrooms are extremely aversive to Juan. Each time his mother takes him into a public restroom and sees one of these hand dryers, Juan begins to scream and hit his mother’s arm. His mother immediately takes him out of the restroom and avoids restrooms with automatic hand dryers in the future. Juan’s mother didn’t intentionally reinforce his screaming and aggression; however, Juan will likely engage in these behaviors if she takes him into a restroom with these hand dryers in the future. This is another great opportunity for functional communication training to teach Juan to escape the unpleasant sensory experience using more adaptive behavior.

Socially mediated escape from attention or social interaction

Just as some attention and social interactions are reinforcing for some children, the same attention or social interactions may be aversive for others. When an adult helps the child escape from these situations, the child’s behavior is potentially reinforced. For example:

Sam loves to play at the playground; however, she does not enjoy other children playing with her. Sam’s mother sits near her and watches as she plays in the sandbox digging holes. When another child approaches and tries to play with Sam, Sam begins to scream and throw sand. Sam’s mother tells the other child that Sam has autism and would rather play alone. When the other child leaves, Sam’s behavior may be reinforced.

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Access and Escape in Action

To see some of the functions of behavior in action watch Functions of Behaviour by Tara Rodas:

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How Many Functions Are There, Really?

Traditional sources say there are 3-4 functions of behavior (access, escape, attention and automatic), however there is a better way to conceptualize the functions of behavior. Cipani and Schock (2010) created a behavioral diagnostic system that expands on traditional models to help us understand behavior on a deeper level. They describe 2 primary functions: access and escape then go on to identify the type of reinforcer and the mode of access (direct or socially-mediated). This method provides a comprehensive approach to understanding the functions of behavior.

Depending on your source, the functions are presented in different ways which can make understanding this concept confusing for students new to the field. Many traditional resources as well as current ones, reference 3-4 functions of behavior: Access, Escape, [Attention] and Automatic. Some resources group attention with access, others present it as a separate behavioral function. Tools, including questionnaires like the Question About Behavioral Function (QABF) and the Functional Assessment Screening Tool (FAST) also provide different behavioral categories. Here we will compare just 3 common models of describing behavioral funciton.

Classic Functions of Behavior

Jamison et al. (2016) present this limited view of function in their presentation ABA in 2016. They describe the 4 primary functions of behavior as access, attention, escape and automatic reinforcement. In this model, behaviors that receive positive reinforcement in the form of an activity or something tangible fall in the access category. The attention category covers behaviors maintained by positive reinforcement in the form of attention. Escape includes behaviors that are negatively reinforced through escaping or avoiding an aversive stimulus. Automatic describes behaviors maintained by a pleasant sensory experience.

Three of these categories cover positive reinforcement, leaving one to describe negative reinforcement. A benefit to this perspective is the simplicity, but the categories of access, attention and automatic are somewhat redundant and unclear. Instructors in many ABA courses present this model when teaching about the functions of behavior. Students of these instructors may feel confused when they encounter alternative conceptualization of this critical concept.

The image below shows the extent to which this model describes behavioral function. The analyst may include more narrative information to further clarify maintaining variables, but the categories themselves fail to provide much description.

Traditional functions of behavior

Identifying Reinforcers to Determine Functions of Behavior

To identify the function of a particular behavior, professionals conduct a functional analysis or functional behavior assessment. This involves either manipulating variables surrounding the behavior of interest or collecting data when the behavior occurs in a more natural setting. The analysts consider what reinforcer occurs as a result of that behavior (or at least within a temporal relation to that behavior).

In their book Applied Behavior Analysis, which is often referred to as the ABA bible, Cooper, Heron and Heward (1987, p. 501-502) describe 2 primary categories of behavioral function with subcategories for each: Positive Reinforcement and Negative Reinforcement. Remember that reinforcement is a stimulus that follows behavior AND strengthens that behavior along some measure (i.e. frequency, intensity, duration, etc.). Positive reinforcement refers to the addition of a stimulus and negative reinforcement refers to the removal of a stimulus.

This view of behavioral function is more detailed than the one described above and starts to dig more specifically into what stimulus is added (positive) or removed (negative) to strengthen the behavior (reinforcement). The subcategories included by the authors are represented in the image below. These subcategories provide more information about the maintaining variables which leads to more accuracy when selecting function-based interventions.

Functions of behavior according to Cooper, Heron and Heward (1987)

Diagnosis of Function

Cipani and Schock (2010) use a slightly different model when describing behavioral function. Their comprehensive approach avoids redundancy while thoroughly capturing all possibilities. This system specifies not only positive reinforcement (access) or negative reinforcement (escape) but also the type of reinforcer and whether another person provides access to the reinforcer (direct or socially-mediated). The authors include additional descriptive language when appropriate such as describing whether attention from peers or adults maintains the behavior.

Understanding behavior at this level helps you develop a plan that effectively addresses that behavior. Grey and Hastings (2005) emphasized the use of function in selecting evidenced-based interventions. Functional behavioral assessment and functional analysis allow the analyst to identify or hypothesize the function of challenging behavior. Once you collect data to determine controlling variables, use this diagnostic tool to describe those variables in detail.

First, identify if the reinforcer is positive or negative. Then, determine what type of reinforcer controls the behavior. Finally, determine if access to that reinforcer requires the presence of another person. Although this model requires 3 steps, it becomes fluid with some practice.

Look at this example:

Your client engages in aggression when asked to perform a task he doesn’t want to do. After looking at descriptive analysis data and observing the behavior yourself, you see that his aggression results in a delay of the task and staff altering how long they expect him to perform the task.

Without conducting a full analysis of the behavior, you can only hypothesize the function. In this example, the behavior is maintained by both the direct escape (delay of onset of the task) and socially-mediated escape (staff shortening the task) of a relatively lengthy task. The task might not actually take a long time to complete, but consider the task from his perspective.

This quick example highlights the benefit of describing function in this way. Now you understand more specifically what aspect of the task he finds aversive. Teaching him to request a delay in starting the task or a shorter task or a even break during the task provides an alternative that addresses the details of what maintains the challenging behavior.

Functions of Behavior according to Cipani and Schock (2010)

Comparing the 3 Models

While the model you choose may impact your ability to choose effective, function-based interventions, they aren’t necessarily mutually exclusive. You may choose to use Cipani and Schock’s model when selecting interventions, but a simpler one when speaking with or training parents or caregivers.

Look at the following example and how each model describes the function of the behavior:

You conduct a functional behavior assessment and determine that your client’s spitting most often results in attention from both his peers and classroom teacher.

The first model described above would put this behavior in the attention category. The second model puts this behavior in the social positive reinforcement category. The third model describes this behavior as maintained by socially-mediated access to attention from both adults and peers. Sure, the information is reasonably similar, but the third example provides a bit more detail that assists you in your search for effective interventions.

Choose the model of functions of behavior that makes the most sense to you and meets the needs of your specific situation. Each model presents unique advantages, but your audience’s understanding of the model might be the most important consideration. Although you use this information to select appropriate function-based interventions, other people likely need to understand your analysis. Parents, RBTs, and payers each read and process your documentation for different purposes. Avoid using language from one of the models that will confuse your intended audience, if possible.

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Determining the Function of a Behavior

How do you know what the function of an individual’s behavior is? Unfortunately we can’t just ask them because even if they could tell us, they’re likely not aware of it themselves. Consider your own behavior for a minute:

Most people could probably tell you why they go to work: to get a paycheck, right? So the function of the behavior “going to work” would be pretty obvious.

But let’s dig a little deeper. What if you consistently work hard to go above and beyond what’s expected of you at work? What might the function of this behavior be? There are actually several possibilities. You might get:

  • Satisfaction from the work you’re doing
  • Praise from your boss, parents, coworkers, teachers, clients, etc.
  • Compensated for doing your job well (i.e. a raise, bonus or commissions)

Unless you stop to think about this, you might not even realize what you’re doing, or why you’re doing it.

Your learners likely don’t know why they do what they do, so how can you figure it out?

ABC Data

ABA relies heavily on ABC data to understand the context of a behavior. Our post ABC Data: The Key to Understanding Behavior goes into detail about what ABC data is and how to collect it…but then what?

Well, that depends on whether the ABC data alone provides a clear function of the behavior. Let’s look at an example.

On an ABC data sheet the data looks like this:

Debra said it was time for schoolJake yelled no and threw his toy toward DebraDebra gasped and Jake delayed going to school, missing the bus
  • In the antecedent column, you write what happened just before the behavior, Debra said it was time for school.
  • In the behavior column, you write Jake yelled no and threw his toy toward Debra.
  • And in the consequence column you write what happened right after the behavior, Debra gasped and Jake delayed going to school.

There might be other antecedents and consequences that also influence the behavior that you might make note of. Maybe Debra forgot to bring Jake’s lunchbox into the room or it’s already in his backpack and he doesn’t know it. Maybe the airplane made a cool noise when it hit the floor.

Which factors might be impacting his behavior? With this data, you can ask yourself, “what is he telling me with his behavior?” What is he accessing or avoiding with the behavior? He gets a small reaction from Debra and he delays going to school. Maybe he’s saying, “I don’t want to stop playing. I would rather stay with you.”

While this example seems pretty clear, often the data is more complex, and a series of challenges may build on each other.

Let’s take this example a little further. The consequence for the first behavior might become the antecedent for the next behavior. 

Jake might be upset that his routine was disrupted by missing the bus and that could trigger another behavior. 

Here we write down what behavior Jake engages in, he cries, stomps his feet and then pushes Debra.  The consequence of this behavior is Debra says, “we have to go now.  I’m going to be late for work.”  This consequence becomes the antecedent for the next behavior which is Jake hitting Debra and then running to his room.  The consequence to this behavior is that Debra follows him and offers to stop to get a doughnut on the way to school. 

We can see through this example that Jake’s behavior escalated pretty quickly and Debra was doing whatever she could just to get him out the door.  What is Jake saying with his behavior?  How about, “I don’t know how to handle sudden changes in my routine and I want you to help me.”  He also gets a doughnut out of the deal. 

The data sheet might look like this:

Debra said it was time for schoolJake yelled no and threw his toy toward DebraDebra gasped and Jake delayed going to school, missing the bus
Debra gasped and Jake delayed going to school, missing the busJake cries, stomps his feet and then pushes DebraDebra says, “we have to go now.  I’m going to be late for work.” 
Debra says, “we have to go now.  I’m going to be late for work.” Jake hit Debra and then ran to his roomDebra follows him and offers to stop to get a doughnut on the way to school

While all this is important information, you may find that ABC data alone isn’t enough to determine the function, and you need to collect other types of data such as questionnaires and scatterplot data.


There are several questionnaires available to help determine the function of a behavior: Motivational Assessment Scale (MAS) and Questions about Behavioral Function (QAFB). In Assessment of the convergent validity of the Questions About Behavioral Function scale with analogue functional analysis and the Motivation Assessment ScaleT. R. Paclawskyj,, J. L. Matson,, K. S. Rush,, Y. Smalls, T. R. Vollmer (2008) determined that these two questionnaires provide similar results.

As an alternative, we have created interactive “quiz” to help determine the function of a behavior (note, this opens in a popup window).

Scatterplot Data

Scatterplot data can also provide insight into the time of day, or day of the week behaviors are more likely to happen. Using a grid to map out the time of day and the day of the week, simply record the number of instances of a behavior in the allotted time.

Download a blank template now!

Analyzing the Data

Once you have all the data assembled, you need to understand what it all means. If you’ve collected the data in a tool, either through your employer, or one you’ve purchased like our AID Document Creation Tool (an add on to the ABLE Support for BCBAs , the program can likely do a lot of the analysis for you. AID, for example, takes the data and creates graphs that make it easy for you to find patterns in the data.

For a less technical approach, you can use something like the Data Triangulation Chart pictured here to collect your findings. While this document has a fancy title, it’s simply a form where you can make notes about the most common antecedents and consequences from each source of data. Download a blank template here:

Click the image below to launch our interactive form in a popup window.

Cipani, E., & Schock, K. M. (2010). Functional behavioral assessment, diagnosis, and treatment: A complete system for education and mental health settings. Springer Publishing Company.

Cooper, J. O., Heron, T. E., & Heward, W. L. (1987). Applied behavior analysis. Merrill Publishing Co.

Grey, I. M., & Hastings, R. P. (2005). Evidence-based practices in intellectual disability and behaviour disorders. Current opinion in psychiatry, 18(5), 469-475.

Jamison, W. J., Hard, A., B. A.,Tara, Allen, C., Clark, J. & Hagy, S. (2016). ABA in 2016. [PowerPoint slides].

Paclawskyj, Theodosia Renata, “Questions About Behavioral Function (QABF): A Behavioral Checklist for Functional Assessment of
Aberrant Behavior.” (1998). LSU Historical Dissertations and Theses. 6855.

T. R. Paclawskyj,, J. L. Matson,, K. S. Rush,, Y. Smalls, T. R. Vollmer. (2008). Assessment of the convergent validity of the Questions About Behavioral Function scale with analogue functional analysis and the Motivation Assessment Scale. Journal of Intellectual Disability Research.

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