Written by Nick Pamment, IKON Trainer.

What actually happens when someone becomes aggressive?

When someone becomes aggressive, it can be easy to focus on the behaviour we can see. This may be a raised voice, threatening language, pacing, confrontation or physical aggression. 

But what is actually happening underneath that behaviour? 

One of the things we need to understand is that aggression doesn’t always begin with a conscious decision. Our brains are constantly assessing what is happening around us, looking for opportunities and potential threats. That threat doesn’t have to be physical. It could be a perceived threat to our health, work, reputation, relationships, sense of control or even our sense of fairness. 

For example, being told that you cannot access something you believe you need could create a strong sense of injustice. The situation may not be physically dangerous, but the brain can still interpret it as a threat that needs to be dealt with. So when we perceive a threat, our emotional and physical responses can change very quickly. 

So, what happens inside the brain when that happens?

Why does the brain respond to threat?

Part of our nervous system is there to keep us safe. 

The brain is constantly taking in information and assessing whether something might be an opportunity or a threat, and whether it is safe or unsafe. From a survival point of view, missing an opportunity is generally less costly than missing a threat, which is one of the reasons our brains can give negative information a lot of attention. 

The amygdala is one of the parts of the brain involved in detecting and responding to potential threats. When something feels threatening, it can contribute to the body’s fight-or-flight response, and this can happen very quickly. 

If someone is angry, frightened or highly distressed, the intensity of that emotion can become part of what the brain is responding to. The body may begin preparing for action, with changes such as an increased heart rate, faster breathing, sweating or shaking. These responses are useful when we genuinely need to deal with danger. But they can also make communication more difficult when the threat is perceived rather than physical. 

The brain is effectively trying to keep us safe… even when the situation doesn’t necessarily require that level of response.  

The important point isn’t that the amygdala simply makes someone aggressive. 

It’s that when someone feels threatened, their emotional and physiological state can change, and that can influence what happens next. 

Understanding that gives us something useful to work with.

What happens when we’re too focused on the threat?

When we experience a strong emotional response to something, our ability to think through information, consider different options and communicate clearly can become harder. The prefrontal cortex is an area at the front of the brain involved in complex thinking and regulating responses. Under significant emotional pressure, the brain’s ability to engage in considered thinking can be affected. 

That can change how someone communicates. 

They may focus very heavily on what they perceive as the problem. They may hear only part of what is being said. They may struggle to take in new information or consider another perspective – something that can sometimes be described as ‘selective hearing’. 

And this isn’t just something that happens to the person who is becoming angry. 

It can happen to us too. 

If somebody is shouting at you, behaving unpredictably or making you feel threatened, your own stress response can start to rise. You can become more reactive, more defensive or more focused on ending the situation immediately. That creates an important question: 

How do we stop our own response from adding to the situation? 

So this is where communication matters. If someone is already experiencing a situation as threatening, unnecessary demands, commands, confrontational body language or an overly assertive approach can potentially add another threat signal. 

That doesn’t mean staff should be passive. There will be situations where clear boundaries and assertive communication are necessary, but the timing and manner of that communication matter. 

These things can help create the conditions for communication rather than adding to the perceived threat. They may give the person more opportunity to process what is happening and consider how to respond. 

This is one of the reasons early intervention matters. Conflict rarely appears from nowhere, and recognising changes in behaviour and communication before a situation reaches its most intense point gives people more options.

What can influence what happens next?

We cannot always control what another person does, but we can influence what happens next through the way we respond. 

When someone is already experiencing a situation as threatening, the way it is handled can either add to the perceived threat or create better conditions for communication. 

That might mean taking a moment before reacting, recognising what is changing, considering how the interaction is being experienced, and choosing communication that doesn’t add unnecessary pressure. 

In practice, that may mean using a calm tone of voice, controlled body language, giving someone space, asking a relevant question or showing that you’re trying to understand what is happening. 

None of these things guarantees that a situation will de-escalate, and there will be times when clear boundaries, assertive communication or additional support are necessary. The situation, the person and the level of risk will all affect what is appropriate. 

But having practical skills that have been rehearsed before can give people more options when pressure is high.

Understanding aggression doesn’t mean excusing it

There is an important distinction here. 

Understanding why someone may become aggressive does not mean excusing aggressive behaviour. People still have a responsibility for their actions. Staff still have a right to feel safe at work. Organisations still need clear processes for managing risk and responding when behaviour crosses a line. 

But understanding what might be happening underneath the behaviour can help us make better decisions. Instead of immediately asking, “Why are they behaving like this?”, we can start asking: 

• “What has changed?” 
• “What might they be responding to?” 
• “What can I do that doesn’t make this situation more threatening?” 

That doesn’t mean accepting unacceptable behaviour. It means responding to the person and the situation in front of you rather than relying on assumptions about why someone is behaving that way. 

Sometimes the most effective response can be surprisingly simple. 

I can recall a situation from a recent session where a colleague asked someone who was behaving in an aggressive manner, “Do you think your behaviour is okay?” 

The question made the person stop and think. 

It wasn’t a command. It wasn’t confrontational. It gave them something to consider. 

That is a useful reminder that communication isn’t always about having the perfect thing to say. Sometimes it is about creating enough space for someone to think. 

What does this mean for how we handle difficult situations?

Aggression can look very different from one situation to another. 

The person may be angry. They may be frightened. They may feel ignored, powerless or treated unfairly. They may be responding to something that has happened outside the interaction entirely. 

We won’t always know the reason. But what we can do is recognise that when someone feels threatened, their ability to process information and communicate can change. 

And we can recognise that the same is true for us. That gives us a practical starting point: recognising what is happening, considering how to respond and understanding that our own response can influence what happens next. 

The aim isn’t to become someone who never feels stressed or uncertain. Those are normal human responses… but the aim is to be better prepared for what happens next. Because when difficult situations arise, people need more than instructions telling them to “stay calm”. They need practical skills they can draw on when staying calm is difficult. 

Training doesn’t stop conflict from happening. It can change what happens next. 

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