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ABA Therapy

The Functions of Behavior and Why They Matter

Dec 5, 2019
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According to behavior analytic research, all behavior happens for a reason. For example, there is a reason why a child, let’s call him Jake, plays asks politely for a snack and a reason why he hits others. In both cases, Jake gets something out of it. Sometimes the reason is obvious (e.g. asking for a snack that he wants likely results in him getting the snack) and sometimes it’s not. Continuing with this example, we know that asking politely for desired things is appropriate behavior and does not warrant any specific behavior intervention at this time. Hitting, however, is a problem behavior that we need to decrease.

Before a Behavior Analyst can provide effective recommendations or strategies for decrease instances of Jake hitting, she must figure out why Jake hits (i.e. the function of the behavior). 

Four Functions of Behavior

There are four functions of behavior in Applied Behavior Analysis. In other words, there are four categories of things that an individual “gets” out of engaging in the behavior.  

  1. Attention: includes praise and reprimands
  2. Escape: from undesired tasks/activities
  3. Tangible: access to a desired item, activity, or food
  4. Automatic (Sensory): preferred sensory input 

Assessing Behavioral Function

Behavior Analysts use a variety of tools to try to determine the function of the problem behavior, including structured interviews, questionnaires, and direct observation of the behavior in the natural environment. Some of the most common questions Behavior Analysts ask to determine behavior function include:

  • What happens directly before the behavior (i.e. the antecedent to the behavior)?
  • What do the behaviors look like in operational terms (e.g. hitting, running away, yelling)?
  • What happens directly after the behavior (i.e. the consequence of the behavior)?

Behavior Analysts ask these questions in order to figure out if there are any identifiable patterns in the problem behavior. 

Going back to our example, let’s say the Behavior Analyst learns that Jake only hits while he is at school. Because more demands are placed on children at school than anywhere else, it could lead her to think that the function of the behavior is escape.

At the conclusion of the assessment period, a Behavior Assessment (FBA) is written. This assessment gives a hypothesis as to why the individual is engaging the target behavior and proposes treatment strategies based on the function of the behavior.

Treatment by Function

The effectiveness of an ABA intervention depends on the individualization of the treatment plan. All individuals are unique and require unique strategies. However, there are some general guidelines for treating behavior by function. 

  1. Teach a replacement behavior (e.g. raising hand could be a replacement behavior for calling out).
  2. Ignore the problem behavior (NOT the learner).
  3. Reinforce, or reward, the replacement behavior.
  1. If the behavior only occurs in the presence of a particular person, encourage that person to spend some fun, “demand-free” time with the learner.
  2. If the task is determined to be too difficult, break it down into smaller steps and reward the completion of each step to build behavioral momentum. 
  3. Help the learner build a tolerance for longer, more difficult tasks using praise and reinforcement. 
  1. Teach the learner to use functional communication to ask for desired items and activities (e.g. asking for a turn on the swing instead of hitting peers who are on the swings).
  2. Ignore the problem behavior (NOT the learner). 
  3. Reinforce the use of functional communication.
  4. Provide clear and consistent expectations as to when and where a learner can ask for (and be given access to) favorite items and activities. 

Automatic (sensory)
  1. Consult an Occupational Therapist (OT) to explore sensory needs.

To revisit our example with Jake, let’s say Jake’s Behavior Analyst wrote and FBA and identified escape as the function of hitting. Furthermore the FBA explains the hypothesis that Jake hits every time he is told to complete a math worksheet. When he hits, Jake gets put in time out and is excused from completing the math worksheet. By understanding this pattern of behavior, Jake’s Behavior Analyst can recommend appropriate strategies. In this case, she recommends breaking down the worksheet into three separate parts and provides a reward for completing each part. She also recommends teaching Jake to ask politely for a break when he needs one. Lastly, if Jake hits he must take his worksheet to time out with him and complete it there. 

If you’re interested in learning more about the functions of behavior and treatment by function or would like a review of strategies tailored to your child, visit and let your clinician know!


Carr EG. Emerging themes in the functional analysis of problem behavior. J Appl Behav Anal. 1994;27(2):393–399. doi:10.1901/jaba.1994.27-393

Carr EG, Durand VM. Reducing behavior problems through functional communication training. J Appl Behav Anal. 1985;18(2):111–126. doi:10.1901/jaba.1985.18-111

Day HM, Horner RH, O'Neill RE. Multiple functions of problem behaviors: assessment and intervention. J Appl Behav Anal. 1994;27(2):279–289. doi:10.1901/jaba.1994.27-279

Durand VM, Carr EG. Functional communication training to reduce challenging behavior: maintenance and application in new settings. J Appl Behav Anal. 1991;24(2):251–264. doi:10.1901/jaba.1991.24-251

McLeod, S. A. (2017, Feb 05). Behaviorist approach. Simply Psychology.

Worcester L, McLaughlin, TF. Comparing Effective Treatments for Attention-Maintained and Escape-Maintained Behaviors in Children with Behavior Disorders; Brief Review and Analysis. International Journal of Basic and Applied Science. 2013;1(3): 621-627

Because the behavioral treatments vary so much by function, it’s difficult to ensure that the most effective and comprehensive treatment option is being implemented without know why the individual is engaging in a specific behavior.

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