top of page

WTF? What's the Function? - Determining the why behind behaviors.

All behavior is communication. It may be a foreign language at times, but it is always saying something. This is one of the most important things to remember when you are struggling with your child's challenging, frustrating, and sometimes dangerous behaviors. Even though it seems to make no sense to you, that behavior means something to your child. ALL behaviors happen for a reason! Determining the reason, a.k.a. "the function", of the behavior provides us insight in how to react to a behavior, helps to determine appropriate replacement behaviors (i.e. what to teach in place of the behavior), and allows us to make informed decisions to change behavior. There are four main functions to all behaviors. That’s right, only four potential reasons a behavior is happening! I am going to guide you through each of these functions, so that you can re-evaluate some of these behaviors as you see them at home or in the classroom and re-think how you will respond to them in the future.

The ABC's of Behavior

So how do we determine the why? To do this, we have to look at what the behavior is providing to the child. What is the child communicating with that behavior? What is the main purpose? To help us to determine this, we will often take data and look at the ABCs. What does this mean? Simple... what happens immediately before and after that behavior. This data is often referred to as ABC data. ABC data stands for: A=Antecedent (before the behavior), B=Behavior (the behavior we are focusing on) and C=Consequence (what follows the behavior).

So typically, behavior occurs in this manner:

1. Antecedent – What happened right before the behavior?

o Examples: Gave instruction, playing with, alone, talking to, etc.

2. Behavior – What did the child do?

o Examples: Hitting, biting, flopping on floor, laughing, yelling, running away, pinching, etc.

3. Consequence – What happens immediately after the behavior?

o Examples: Given attention, verbal redirection, food given, work terminated, nothing, etc.

Now let’s look at our four functions of behavior, and see how they fit into our ABC sequence.


Sometimes a child may engage in a behavior to get attention from others (i.e. parent, sibling, teacher, peer, etc.). Attention can take many forms, and include both positive and negative attention. Any attention is attention (i.e., laughing at something silly your child is doing, looking at your child, talking to your child, giving help, using that famous ‘warning tone’ with your child, and even yelling at your child).

ABC Example:

o Antecedent – A child is asked to put on her pajamas

o Behavior – She runs around the room laughing and engaging in silly antics

o Consequence – Dad laughs and tells her she is silly

In this situation, the behavior of laughing/silly antics/running around the room is being reinforced by the attention she knows she will likely get from her dad. This means that when she is possibly feeling ignored, she is likely to exhibit these behaviors to get attention from her dad in the future.

Access to Tangibles

Sometimes children may engage in a behavior to receive access to a tangible item or a preferred activity. You will hear this function referred to as Tangible or Access.

ABC Example:

o Antecedent – A child drops his plate on the ground during lunch

o Behavior – The child cries and screams

o Consequence – Mom provides a new plate and new food

In this situation, the crying and screaming had the function of getting a new plate of food. The behavior, or screaming/crying, has become reinforced. This means that in a similar situation, the child is more likely to cry and scream because they got food when they cried and screamed the last time.


Children may engage in a behavior to remove themselves from an undesired situation, interaction, activity, etc.

ABC Example:

o Antecedent – It’s dinner time, but a child is not hungry

o Behavior – Child throws their dinner plate on the ground

o Consequence – Mom says "well I guess you are not eating tonight" and removes the dinner items

In this situation, the throwing the plate of food had the function of removing the dinner demand. The throwing may have become reinforced, as they removed situation of having to eat for the time being. The next time it is time to eat and they do not want to, the child is more likely to throw their plate because dinner was delayed/removed last time.


Children will engage in behaviors because it feels good to do so, providing an internal stimulus that the child enjoys OR the child engages in the behavior because pain is removed or decreased (pain attenuation). If you suspect that the function is related to a medical condition, you should contact your child’s physician.

ABC Example:

o Antecedent – Often unknown because it is not observable

o Behavior – Child is rocking and humming

o Consequence – There is some form of internal reinforcement, possibly a sensation

In this situation, the behavior provides its own reward. Automatic/Sensory behaviors are the most difficult behaviors to decrease. The reason for this is that we cannot easily remove the reinforcing consequence (i.e. the internal stimuli) and it is difficult to replace this behavior with something that is appropriate that allows for the same stimulation.

As you can see all behaviors have a function, and sometimes a behavior can have multiple functions! For example, escaping a situation can also mean receiving attention for the behavior. One of the biggest reinforcers for a child’s problem behavior is attention. Children LOVE attention!! Often a child will receive attention for what they do wrong to stop their behavior (i.e. Mom stops what she is doing and tells them to stop). If they had not engaged in the problem behavior, Mom would not have stopped what she was doing, and the child would not have received her attention. Another common way of stopping the problem behavior is giving the child a preferred item or snack to calm them down. Although it works at that moment, it makes the problem behavior more probable in the future


Now we know the function...but how does this help?

This is why we look at the ABC data. We want to look at the challenging behaviors and see what the frequent antecedents and consequences are. This can help us figure out patterns of behaviors. With this information, we can then alter future antecedents, reconsider the consequences, and develop appropriate replacement behaviors to teach (look for a future article on this!). For example, if we notice a pattern that there is always a tantrum when Mom says it is time for bed and the common consequence is extra hugs and reassurances (i.e. Attention) and a delay in bedtime (Escape), we can then develop a plan of action:

  • We might develop what is called an antecedent strategy (i.e. something to set us up for success) such as giving a visual timer for bed time, providing a countdown for bed time, having a bedtime routine that starts with preferred activities (i.e. lotion, book).

  • We would also set firm consequences that do not allow reinforcement of those tantrum behaviors (i.e. no hugs, no extra time when behaviors occur) such as firm redirection and remove Mom from the room when tantrum behaviors start.

  • We would want to teach an appropriate replacement behavior(s) to replace the challenging behaviors (i.e. teaching them to ask for a hug (attention), teaching them to ask for 2 more minutes (delay).

  • We also might set up a reinforcement plan for the child for if they can go to bed quietly (i.e. choice of breakfast in the morning).

Understanding the why of the behaviors that your child is engaging in can help you to develop effective strategies to both prevent problem behaviors from occurring and to teach your child more appropriate ways to meet their needs. So that behavior that keeps popping up every day that has you shaking your head saying ‘where did that come from?’: here is a plan of action!

  1. Observe your child and take some data. There is a link to a simple ABC data form at the bottom of this article that you can easily download and use!

  2. Take a look at the data and figure out the 'why' behind the behavior.

  3. Set some antecedent strategies and determine a replacement behavior that you are going to teach. Once you figure out the function it will make determining an alternative behavior that still meets the same need as the problem behavior that much easier! Reinforce the alternative behavior that you are teaching!

  4. Have patience! Remember, it takes time to develop new routines and behaviors. Be consistent and look for progress, not perfection!

  5. Enjoy seeing the new and more appropriate behaviors develop before your eyes! Know that you can help your child to learn and grow even from a less-than-ideal starting place.

Please remember that these are general suggestions. If you have individual concerns regarding your child’s behavior that you would like assistance with, please reach out to get professional assistance. You can locate a qualified service provider in your area by visiting the Behavior Analyst Certification Board’s (BACB) website and search for service providers in your area. The BACB website contains a list of all Board Certified Behavior Analysts (BCBAs). You can also find qualified service providers by visiting the Autism Speaks website. They have great Resource Guide that allows you to search for services in your state. - Jamie

61 views0 comments


bottom of page