When Behaviour Speaks Louder Than Words

The "Why" Behind Behaviour in Children with Autism (Post 1 of 5)

TL;DR: Behaviour in children with autism is never random, it is communication. A Functional Behaviour Assessment (FBA) helps us identify the function of a behaviour: what it is achieving for the child. There are four primary functions: Sensory, Escape, Attention, and Tangible (SEAT). This week's challenge: pick one puzzling behaviour and spend the week observing it rather than stopping it. That shift from reaction to curiosity, is where understanding begins.

Does this sound familiar?

A child tips over their chair. Another refuses to leave the reading corner. A third screams or bolts the moment the routine changes. And there you are  in the middle of it all wondering: what is actually going on, and how do I help?

If you work with children with autism between the ages of 4 and 18, you already know that moments like these are not rare. What you may not always have is a clear framework for making sense of them. That is exactly what this series is for.

Over the next five weeks, we are going to go beneath the surface of behaviour - not to judge it, manage it, or eliminate it at any cost, but to understand it. Because here is the truth that changes everything once it really lands: Behaviour isn’t random. It is communication.

Why Behaviour Happens

Children with autism often experience the world in ways that are fundamentally different from their neurotypical peers. Sensory input can feel amplified or completely muted. Transitions can feel genuinely destabilising. Social cues can arrive scrambled or not at all. And for many children, verbal expression is limited, unreliable, or simply unavailable in moments of high stress.

When a child does not have the tools to communicate what they need, the body and mind finds another way. That other way is what we call behaviour.

This is why responses like "stop that," "sit down," or "you need to calm down" so rarely work in isolation. They address the surface. They do not touch the source. Before we can respond effectively, we need to shift the question  from "how do I stop this?" to "what is this behaviour doing for this child right now?"

The Tool That Helps Us Answer That Question

A Functional Behaviour Assessment  or FBA is a structured, evidence-based process used by educators and support teams to identify the function of a challenging behaviour. In plain terms: it helps us figure out what the behaviour is achieving for the child.

You do not need to be a behaviour specialist to understand how it works. The process follows five steps:

Define the behaviour clearly. Not "he acts out" - that tells us nothing. Instead: "Marcus drops to the floor and covers his ears when the bell rings." Specific, observable, and measurable.

Collect ABC data. ABC stands for Antecedent–Behaviour–Consequence. What happened right before? What did the behaviour look like exactly? What happened immediately after? You are building a map of the pattern.

Identify the pattern. After a few days of data, patterns almost always emerge. Does it happen during math? Before transitions? When a specific peer gets too close? The pattern points toward the function.

Name the function. What is the behaviour achieving for the child? This is the heart of the FBA, and we will spend the rest of this series unpacking it.

Build a response. Once you know the function, you can design an intervention that addresses the root cause, not just the symptom.

The Four Functions: A First Look

Research points to four primary functions of behaviour. Educators often remember them with the acronym SEAT.

Sensory: The behaviour meets an internal sensory need. Rocking, humming, hand-flapping, drumming, chewing on clothing. These behaviours feel good to the child regardless of what anyone around them does. The nervous system is doing what it needs to do.

Escape: The behaviour removes or delays something uncomfortable. A demand, a task, a sensory experience, a social situation. This is one of the most commonly misread functions in classrooms, and it gets its own dedicated post next week.

Attention: The behaviour produces engagement from adults or peers. A professor of mine in grad school put it simply: positive or negative, it is all the same to the child. Attention is the goal, and any attention will do.

Tangible: The behaviour gains access to something concrete. A preferred toy, a snack, iPad, a specific seat. When conventional requests are not available to the child, behaviour becomes the request.

Each of these functions will get a full post of its own. For now, what matters is this: every behaviour fits somewhere in this framework. And once you know where, everything about your response changes.

From My Classroom

In my experience, out of the four functions of behaviour, sensory is often the most challenging to address, not because it is harmful, but because it can be distracting to the rest of the class, and because it rarely follows a predictable script.

I had a student who cycled through different sensory-seeking behaviours. He would drum constantly, and even after we taught him to request drumming breaks, the drumming never fully stopped. After a while it evolved, drumming became drumming and singing. He was musically motivated, and his nervous system knew it. The only time he was truly still was during instructional videos or classroom sing-alongs. That told us a great deal about how to reach him - though our time together ended before we could fully explore it.

Another student would randomly begin spinning during group games. It looked disruptive from the outside, but it was simply his nervous system processing delight. He was happy. He was excited to be playing with his peers. His body just had its own way of showing it.

A third case has stayed with me. This student's behaviour shifted suddenly, and the shift itself was the signal. Random crying, difficulty tolerating gym lessons, not keeping his hands to himself, jumping vigorously. It was unusual even for him, and nothing in the classroom environment explained it.

After some data collection, I called home and asked some careful questions. It turned out the family had temporarily relocated while their house was being renovated. No big announcement, no visible disruption at school,  just a quiet but significant change in this child's world. When I mentioned how much it seemed to be affecting him, the parent said something along the lines of, "We didn't think it would affect him so much."

They weren't being dismissive. They simply hadn't realised. The child was carrying real stress, and because he didn't have the language to name it, it came across as behaviour.

We couldn't have found that through ABC data alone. What unlocked it was a phone call, a trusting relationship with the family, and the willingness to look beyond the classroom walls. It is a stark reminder that children with autism experience stimuli  and life changes  far more deeply than we often realise. The environment doesn't have to be loud or dramatic to be overwhelming. Sometimes just the absence of the familiar is enough.

One Thing to Try This Week

Pick one behaviour you see regularly in your classroom or at home, something that frustrates you or leaves you puzzled. Instead of focusing on how to stop it, spend this week simply observing it.

Note what happens right before. Note what happens right after. You don't need a formal data sheet. A sticky note works. You are not solving anything yet, you are just starting to listen.

That shift in posture, from reaction to curiosity, is where everything begins.

Coming Up Next Thursday

Next week we are going inside escape and avoidance. Also, the most misread function in classrooms, and the one most likely to be mistaken for defiance. I'll share what it really looks like when a child runs, shuts down, or refuses and what finally made the difference for one student once we understood what the behaviour was really telling us.

See you Thursday!

Sources & Further Reading

Cooper, J. O., Heron, T. E., & Heward, W. L. (2020). Applied behavior analysis (3rd ed.). Pearson.

O'Neill, R. E., Albin, R. W., Storey, K., Horner, R. H., & Sprague, J. R. (2015). Functional assessment and program development for problem behavior (3rd ed.). Cengage Learning.

Individuals with Disabilities Education Act, 20 U.S.C. § 1400 et seq. (2004). https://sites.ed.gov/idea/