Intro to ABA 4: Functions

Welcome to the fourth release in the Intro Series: Functions.


Hopefully by now you understand that behaviours occur in contingency (Part 1) and are maintained by reinforcement (Part 2), which is either positive (something is added to the environment) or negative (something is removed or avoided) (Part 3). This final post will look into Functions of behaviour.

There are Four Functions of Behaviour:

  1. Sensory (Automatic)
  2. Escape / Avoidance
  3. Tangible
  4. Attention (Socially mediated)


This is when the purpose of the behaviour has an internal consequence that is maintaining the behaviour. For instance, something that feels good, or relieves pain, anxiety, etc.. Cooper, Heron, Heward (2007) state that “some behaviours do not depend on the action of others to provide an outcome: some behaviours directly produce their own reinforcement”.  This is something that does not require another person. Self-stimulatory (aka “stimming”) is often associated with people with Autism or Developmental Disabilities, but every person engages in behaviours that have a sensory behaviours. Although some are considered more socially acceptable, but can still be found annoying to some people. For instance, chewing gum, humming or whistling, tapping feet while sitting, thumb sucking, etc. etc.. What is your own behaviours that serve a Sensory Function?

Escape / Avoidance

This is when the purpose of the behaviour is to get away from an item, an interaction, an animal, an activity. These are usually things that the person finds “aversive” or unpleasant and these are different for each person, and depending on the situation. Cooper, Heron, Heward (2007) state that “many behaviours are learned as a result of their effectiveness in terminating or postponing aversive events”. People have fears of spiders, or may find them unpleasant. I will try and remove the spider using a glass or container and newspaper (if its relatively small). Other people would hit it with a shoe and kill it straight away, and some run, scream and jump on to a higher surface. I find public speaking a little nerve wrecking; some people love it and some people absolutely detest it! These people may do anything to get out of speaking in public. Behaviours that are maintained under this function are typically working under negative reinforcement (see Part 3 for more information). Can you think of another example of behaviours that function as escape and/or avoidance?


This is when the purpose of the behaviour is to get stuff. Food, clothes, jewellery, phones, iPads, toys, etc. etc.. Going into the kitchen to get food, or going to a shop to buy a new toy, asking your friend to let you use their phone, are all behaviours that have a tangible function. Getting access to these things are typically maintained by positive reinforcement as the item is added to the environment (see Part 3 for more information). Cooper, Heron, Heward (2007) state “many behaviours result in access to reinforcing materials or other stimuli”. There are often common phrases and jokes that people say they would do anything for, mine would be chocolate. What’s your vice?


This is when the purpose of the behaviour is to interact, communicate, either vocally or non-vocally (signs, gestures, eye contact/joint attention, touch, etc.). We have evolved as species that live in communities and families and socially mediated reinforcement is valuable to us. Behaviours that get attention, initiate interactions or conversations or respond to people serve as an attention function. These can be both positive or negative depending on their intentions. I’m sure we’ve all experienced when we focused on something important and our ‘playful’ friend keeps poking us or trying to distract us. They may be trying to get a reaction from you that isn’t pleasant, “Leave me alone! God you’re so annoying!”. A example of a positive interaction may be a toddler reaching out his arms to be picked up. These behaviours (playful friends attempts to distract you or the toddler with arms outstretched) are both functioning as attention. Cooper, Heron, Heward (2007) state in relation to problem behaviour, which can “result in immediate attention from others, such as head turns; surprised facial expressions; reprimands; attempts to soothe, counsel, or distract; and so on”, which could inadvertently reinforce (maintain) that problem behaviour.


Identifying the function of a behaviour can help interventions be developed more successfully through a Functional Assessment. Cooper, Heron and Heward (2007) state that, “although FBA [Functional Behaviour Assessment] does not identify which interventions will be effective in treating problem behaviour, it does identify antecedents that may trigger problem behaviour, potential behavioural deficits that should be remedied, and reinforcement contingencies that can be altered” (page 513). Researchers have investigated and supported that investigating the function of a behaviour can be integral to the development of a successful intervention (Beavers et al, 2013; Hanley, Iwata & McCord, 2003; Iwata et al, 1982; Iwata et al, 1984; Jessel et al, 2018; Jessel et al, 2019). Tailoring the intervention to the function will ensure that the intervention is successful and has the highest level of social validity. This means if a behaviour occurs that serves a attention function but is not appropriate (for instance a child hits their peer to get attention from adults), then teaching them how to appropriately initiate with adults is a highly effective approach to intervention and reducing this aggressive behaviours. This analysis also focuses on observable events, which helps develop interventions (avoiding explanations like, “child hits peer because he’s frustrated”). Jessel, et al (2019) state that effective functional analyses “is likely to correspond with better treatment outcomes”. Recently, researchers have also shown that developing an intervention that incorporates teaching appropriate behaviour that help serve all functions is also an effective approach. This shows that functions are an important consideration

 < — Return to Intro Series 


References/Further Reading or Listening

Beavers, G. A., Iwata, B. A. & Lerman, D. C. (2013). Thirty years of research on the Functional Analysis of problem behaviour. Journal of Applied Behavior Analysis,  46, 1-21.

BehaviorBabe, (2017, Feb, 3). Functions of Behavior (Behaviorbabe) / slower version. Retreived from:

Cooper, J. O., Heron, T. E., & Heward, W. L. (2007). Applied Behaviour Analysis (2nd ed.) New Jersey: Pearson Education, Inc

Hanley, G. P., Iwata, B. A., McCord, B. E., (2003). Functional analysis of problem behavior: A review, Journal of Applied Behavior Analysis36(2), 147-185.

Iwata, B. A, Dorsey, M. F., Slifer, K. J., Bauman, K. E., & Richman, G. S. (1982). Toward a Functional  Analysis of Self Injury. Analysis and Intervention in Developmental Disabilities2, 3-20

Iwata, B. A., Pace, G. M., Doresey, M. F., Zarcone, J. R., Vollmer, T. R., Smith, R. G. & Willis K. D. (1994). The Functions of self-injurious behaviour: An experimental-epidemenological analysis. Journal of Applied Behaviour Analysis, 27, 215-240.

Jessel, J., Hanely, G. P., Ghaemmaghami, M., & Metras, R. (2018). An evaluation of the single-session interview-informed synthesized contingency analysis. Behavioral Interventions, 1-17.

Jessel, J., Metras, R., Hanley, G. P., Jessel, C., & Ingvarsson, E. T. (2019). Evaluating the boundaries of analytic efficiency and control: A consecutive controlled case series of 26 functional analyses. Journal of Applied Behavior Analysis, 9999(0), 1-19




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