The 4 functions of behavior are avoidance, access, attention, and sensory. Understanding each function may help you replace unwanted behaviors with desired behaviors.

The function of a behavior is its purpose. For example, a person ignoring instructions might be trying to avoid the requested task, or someone acting out might be seeking attention.

Applied Behavior Analysis (ABA) is a system of analyzing and changing behavior through positive reinforcement for desired behavior.

In ABA, the therapist’s goal is to reinforce preferable, alternative behaviors that meet the same need as existing unwanted behaviors.

Before they can do this though, they must first identify the function of the target behavior.

A person engaging in avoidance behavior is trying to escape a situation or avoid a task or activity they don’t want to do. Avoidance behavior can take several forms.


Examples include:

  • A student leaves a classroom without permission.
  • A person walks away from a difficult conversation.
  • A child runs away from their parent.

Disruptive behavior

Examples include:

  • A student pushes their work materials off their desk.
  • A child argues with an adult.
  • A person argues with their spouse.

Off task behavior

Examples include:

  • A student engages socially with a peer during work time.
  • A child plays with a toy they find while tidying their room.
  • A person scrolls through social media instead of vacuuming.

Reasons for avoidance can vary.

A person might be experiencing fear or anxiety about the situation. They may feel overwhelmed or frustrated by their required task. Or they might simply lack the motivation or interest.

Interventions for avoidance behavior should be done with empathy and sensitivity to avoid worsening the underlying issue.

For example, if avoidance behavior results from fear, forcing a child to persist with the activity or situation may increase their anxiety and cause unnecessary stress.

A person’s behavior can get them access to tangibles or preferred activities. It’s the opposite function of escape.

A tangible is something physical, like toys or food.

Examples include:

  • A student cuts into the gym line to have a turn at playing sooner.
  • A child shoves and grabs to get a toy someone else is using.
  • A person lies on their resume or in an interview to get a job.

Access behavior can be learned. For instance, if a child learns that crying works to get them an extra treat, they’re likely to repeat the behavior.

Some behaviors have an attention-seeking function.

Examples include:

  • A student acts silly to make their classmates laugh.
  • A child whines or throws a tantrum.
  • A person interrupts a conversation.

Like access behavior, attention-seeking behavior is often repeated if a person gets the attention they want.

Some experts believe that attention itself isn’t the end goal. Instead, attention is a means of attaining other valued objectives like:

Sensory behavior is something a person does because of how it makes them feel.

Examples include:

  • A student taps their pencil on their book or bounces their leg under their desk.
  • A child plays with their hair or sucks their thumb.
  • A person scratches an itchy rash.

Sensory behaviors can provide relief, like fanning yourself on a hot day. They can also invoke pleasure, such as when you eat delicious food.

The sensory function is a type of automatic reinforcement. This means that it’s a behavior that reinforces itself without help from other people or the person’s environment.

Subspecialties in ABA

ABA is widely known as an autism therapy, but practitioners use it for allistic people too. ABA subspecialties outside of autism and developmental disabilities include:

  • health and fitness
  • brain injury rehabilitation
  • behavioral sports psychology
  • public health
  • behavioral gerontology
  • behavioral pediatrics
  • clinical behavioral analysis
  • substance use disorders
  • child maltreatment prevention and intervention
  • education
  • organizational behavior management
  • environmental sustainability
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A functional behavior assessment is part of the planning process for ABA therapy. It allows the clinician to determine the function of the behavior of concern, so they can create an appropriate intervention.

For example, a child’s tantrum with an avoidance function needs a different solution than a meltdown motivated by a desire for access to something.

It’s also important to understand the cause of the function. Avoidance behavior stemming from overwhelm may need more support than avoidance attempts to escape boredom.