What Is Challenging Behaviour? Understanding the ABCs of Behaviour
If you’ve ever tried to convince a toddler that no, ice cream is not a breakfast food, then you’ve probably witnessed “challenging behaviour” in action.
And if you’ve ever tried to reason with a teenager about why Wi-Fi can’t magically fix itself, you might have wondered whether you should add “behaviour analyst” to your CV.
Hi — I’m Sim. I’m a soon-to-be MSc graduate in Applied Behaviour Analysis (Bangor University, 2025), a dad of three, a lover of motorcycles (which my partner gently discourages for “safety and budget” reasons), and someone who finds human behaviour endlessly fascinating — especially the challenging bits.
I’m also a firm believer that every behaviour, no matter how confusing, makes sense when you know what came before it and what happens after. That’s the heart of the ABCs of Behaviour.
A is for Antecedent — “What set the stage?”
Every behaviour has a trigger, even if it’s not obvious. In behaviour analysis, we call this the antecedent — the thing that happens just before the behaviour.
It could be as simple as a demand (“Please tidy your room”), a transition (“Time to leave the park”), or even something internal like tiredness or hunger.
When my son was younger, he’d often ask for snacks right before dinner. I used to say no automatically — I didn’t want him to fill up or develop the habit of grazing all evening. But I noticed a pattern: when I refused, he’d quickly become irritable, snapping over small things or picking fights with his sister.
At first, I saw it as defiance — a test of boundaries. But over time, I realized it wasn’t about food so much as control and emotional regulation. Kids don’t always have the language to express boredom, stress, or the need for comfort, so “Can I have a snack?” becomes shorthand for “I need something to help me feel better.”
Research shows that children often use eating cues to regulate emotion or signal unmet needs like attention, rest, or reassurance. Once I started responding differently — offering choices like, “We’re not doing snacks now, but would you like to help me set the table or have a glass of water while we chat?” — the irritability faded. He felt heard and involved, and our evenings got calmer without adding more food.
Sometimes, small environmental tweaks can make big behavioural changes — a principle supported by decades of applied behaviour analysis research (Cooper, Heron & Heward, 2020).
B is for Behaviour — “What actually happened?”
This one sounds obvious, but it’s where many people trip up.
A behaviour isn’t just “being naughty” or “acting out.” It’s any observable action that can be measured — something you can see or hear.
Instead of saying, “He was being rude,” behaviour analysts describe what was said or done: “He shouted, ‘No!’ and folded his arms.”
It sounds clinical, but it’s actually freeing — because once you describe challenging behaviour clearly, you can change it.
I use this same lens while building websites or editing YouTube videos. If something doesn’t work, I don’t just say, “The site is broken.” I describe what’s happening: “The link redirects to the wrong page after login.” That precision helps me tackle the issue. Challenging behaviour is the same — we can only change what we can define.
C is for Consequence — “What happens next?”
Here’s where things get interesting. The consequence is whatever happens immediately after the behaviour — and it determines whether that behaviour will happen again.
Sometimes, the consequence is attention (“Stop that!”), escape (“Fine, I’ll do it for you”), or access (“Okay, just one biscuit”).
Even when parents or staff don’t mean to, they can unintentionally reinforce the behaviour they’re trying to stop.
Career paths into ABA tutors and support workers
I once told one of my kids, “We’re leaving the park now.” Cue a loud protest. I tried to reason, negotiate, distract — all the classics. Eventually, I said, “Fine, five more minutes.”
What did I just teach? That protesting gets more playground time. Guess what happened next week? Same protest — faster and louder.
That’s not bad parenting; that’s a perfect example of reinforcement history in action. The child learned what worked.
As behaviour analysts say, behaviour is a product of its consequences.
So, what is challenging behaviour?
“Challenging behaviour” is simply behaviour that challenges us — because it’s intense, frequent, or socially disruptive.
According to Emerson (2001), it’s behaviour that “places the person or others at risk or limits access to community settings.”
But — and this is key — behaviour that challenges is still communication.
Whether it’s a child screaming, an adult refusing, or a colleague snapping in frustration, the behaviour is telling us something about unmet needs or ineffective skills.
Once we understand the ABCs, we can move from blame (“They’re doing it on purpose”) to curiosity (“What are they trying to say?”).
Why the ABC model works
The ABC framework has decades of evidence behind it. It’s the foundation of Positive Behaviour Support (PBS) and Applied Behaviour Analysis (ABA), used in schools, health and social care, and family settings.
Start with our friendly PBS intro
By analysing antecedents and consequences, we can identify the function of behaviour — that is, what the person gains or avoids through it.
Research consistently shows that interventions based on function are more effective and ethical than punishment-based approaches (Hanley, Iwata & McCord, 2003).
As someone with a background in mathematics, I love the clarity of this logic. Every behaviour is like an equation: if we change the variables before or after, the result changes too.
Reframing the challenge
When I first learned about the ABCs, it clicked in the same way solving a tough algebra problem used to (yes, I was that kid).
The “unknowns” of behaviour stopped feeling random and started to make sense.
And once you understand that every tantrum, refusal, or meltdown has a purpose, you start to see behaviour not as defiance, but as data.
It’s what drew me to study ABA seriously, and why I’m so excited (and a little nervous) to be graduating soon.
My goal — whether I’m analysing behaviour, cooking something new from one of my hundred cookbooks, or helping an organisation embed PBS values — is to make a small, positive difference in how people are understood and supported.
Final thought
Challenging behaviour isn’t “bad behaviour.” It’s information — sometimes messy, sometimes loud, but always meaningful.
If we pause, observe the A, the B, and the C, and respond with understanding instead of frustration, we start to turn conflict into communication.
That’s where real change happens — quietly, compassionately, and one interaction at a time.
And maybe, just maybe, with a snack break before dinner.
References
Cooper, J. O., Heron, T. E., & Heward, W. L. (2020). Applied Behavior Analysis (3rd ed.). Pearson.
Emerson, E. (2001). Challenging Behaviour: Analysis and Intervention in People with Severe Intellectual Disabilities (2nd ed.). Cambridge University Press.
Hanley, G. P., Iwata, B. A., & McCord, B. E. (2003). Functional analysis of problem behavior: A review. Journal of Applied Behavior Analysis, 36(2), 147–185.