The link between trauma and behaviour - a basic introduction

Wattle Place works with many people who live with life-long impacts of trauma, and we are committed to helping them minimise those impacts as much as possible. However, most of their life is spent out in the wider community, away from the support of Wattle Place. So, we would like the wider community to become a safer place for them too. This will only be possible if the wider community has a better understanding of trauma and its impacts on behaviour.

We want the wider community to recognise the people “behind” the trauma, and know as we do, that they are much more deserving of our admiration and understanding, than they are of our judgement and anger.

So, what IS the relationship between behaviour and trauma?

At the most basic level, trauma has a profound impact on the brain, and the brain, in turn, greatly impacts our behaviour.

The first thing to explain is that everyone’s brain automatically responds to all input in a specific sequence, literally from the lower to the higher parts of the brain. This image (from may help you to visualise the sequence.


The most basic, most instinctual part of our brain (referred to in this diagram as the reptilian brain) is continually and instantaneously scanning for threat, it’s number one job is to ensure our immediate survival. If the input (sight, sound, smell, sensation) that it scans is familiar and known to be safe, we don’t even notice this constant scanning.

If it detects a threat, however, the “next” part (the “mammalian” brain in the diagram) will instantaneously respond. This is where the “flight, fight or freeze response” will kick in. A person experiencing the flight or fight response may appear agitated, very anxious or confused or may shout in anger or frustration.

This part of the brain will also trigger responses in the body at the same time, such as increased heart rate, a surge of adrenaline, etc. (to prepare the body for flight or fight). It also directs all its focus towards the threat itself, which means things irrelevant to the immediate threat may not be processed, such as time, bystanders, etc. This all happens instantaneously and automatically – without thinking. The “freeze” part of the response can happen when the threat is just too overwhelming, or our ability to escape or defend/protect ourselves is compromised, the brain will basically stop processing anything and just maintain heartbeat, breathing, etc. This is thought to be a primal protective factor to inhibit pain and fear that we are unable to tolerate. Someone experiencing the freeze response may be very distracted, slow to respond, vague or disconnected from what is happening around them.

If the stress response is successful in removing or lessening the threat, the natural sequence means the “higher” (neo cortex) part of the brain can then engage. Once that happens, we are able to think, apply reasoning and logic to analyse the situation, calm ourselves down, then make conscious decisions about what to do next.

Lasting impact

Key to understanding the impact of trauma on behaviour is to understand that trauma actually changes the way our brain works. A simple way to think of it is that the “fight, flight or freeze” response gets “stronger” (or more reactive), the more intensely it activates, the more often it activates, and the younger the age at which it activates. The age of the person is very significant because a child’s brain is still developing, so the impacts of this intense (and/or repeated) stress response on the developing brain are even more profound and pronounced. This heightened reactivity, or sensitivity, becomes “hard wired”.

What this means is that, even once the actual traumatic event is no longer a threat, the brain remains hyper-sensitive – like it’s waiting to have to respond to the threat again at any moment. Any input to the brain that “reminds it” of the previous traumatic threat, will immediately and automatically “trigger” the fight, flight or freeze response, basically tricking the person into thinking, feeling and sensing as though they ARE back in that traumatic event, before the higher part of the brain even has time to “realise” that this input is not actually a threat at all. This is what people refer to as being “triggered”.

What might this actually look like?

In this hypothetical scenario, Jamie experienced long term physical abuse at the hands of an authority figure when he was a child. The abuser would be most violent when they were drunk, and every time they got drunk, they put on a particular song and played it over and over. The abuser was eventually removed from Jamie’s life. His life became very safe and he was well nurtured after that, but he never received treatment for the trauma that he suffered. He basically just got on with his now much safer life, although he experienced lots of difficult days.

One day, as an adult, Jamie is doing his grocery shopping when the song that used to play when he was being abused starts playing over the speaker.

Because his brain is already hard-wired to perceive that sound as a significant threat, it instantly clicks into the stress response (fight, flight or freeze). He becomes agitated, pacing up and down, muttering things to himself. Other people in the supermarket start staring at him. He starts yelling at them to stay away and retreating from anyone who gets too close.

The stress response is very intense because the brain knows that that song was indeed associated with actual harm, on many occasions. That intensity can mean that the brain gets “stuck” in the heightened stress response, inhibiting “access” to the neo cortex, where Jamie would otherwise recognise that he is not actually under threat in this situation.

The difference you can make

Of course, it is not an expectation that, after reading this blog, you will be able or expected to de-escalate a person who has been triggered. It can be a confronting thing to experience and is very unpleasant for all involved. We do hope, however, that, if you are in the presence of someone who is behaving disproportionately angry, erratic, argumentative, distressed, etc., you will think more about the possible reasons behind the behaviour. We hope that you would try to judge that person less harshly, and respond with less anger, possibly even show some compassion if the situation allowed.

When someone is experiencing a trauma response, the responses from people around them have the potential to either add to or lessen the intensity of their response. So, a calmer, safer response is likely to be more beneficial in this situation than a heavy-handed, angry response.

In Jamie’s situation, for instance, if you didn’t consider that trauma might be behind his response, you might stare or swear at him, or approach him forcefully, telling him to calm down. This may heighten Jamie’s fear and his threat response.

If, however, you were to ask yourself, “What has made him act this way?”, you might at least be able to calm other people around you down so that the situation doesn’t become more intense. While you may not be able to confront Jamie directly, you could help make the situation safer for him and everyone, just by taking a more considered approach. That is the difference a little bit of knowledge can make.

This is a very simplistic summary of information found in the resources listed below. There is so much to learn about the impacts of trauma on the brain and body, including strategies that can be used to lessen those impacts. These would be a good starting point if you would like to learn more.


What Happened to You – Dr Bruce Perry & Oprah Winfrey
The Body Keeps the Score: Mind, Brain and Body in the Transformation of Trauma – Bessel Van Der Kolk
blue knot foundation website –