Biology 101: Defensiveness in the brain.

November 30, 2022

Brain with a switch between 'Rational human being' and 'Beast mode'

The brain is a complicated organ; a piece of organic wetware that stymies those who turn their gaze around to try and look closely at it. But over time, neuroscientists are beginning to uncover a better understanding of its inner workings.

An age old philosophical question goes, "Is the way I act a result of nature or nurture?" In other words, was I born the way I am or am I the result of the environment in which I grew up?

The latest research hints that it is actually more of a two-way and than a mutually-exclusive or. Our biology primes us for learning from our environment, and in turn our biology is programmed by these integrated experiences.

We’ve already explored the idea that conditioned responses are learned in childhood, but with regards to conflict it’s worth looking closer at how exactly our bodies try to keep us safe.


Let’s consider what happens in the brain when we experience a defensive response.

Our senses provide a window out to the wider world. Hearing, seeing, smelling, touching, tasting…our bodies are physically tuned to detect this information and send the raw signals to a part of the brain called the thalamus. Here, the stimulus is funnelled onwards to one of two neurological pathways:

  • Pathway 1 is thinking, which allows us to become aware, feel the emotion, comprehend the meaning, and ultimately choose an appropriate action.
  • Pathway 2 is instinctive defense, which takes immediate action to protect us from harm and engages without any conscious thought.

We don’t get to choose which of these paths the brain’s processing will take. As raw information flows into the thalamus, a little bit of it runs by the hippocampus (which stores all of our life’s knowledge, memories, and experiences). In essence, this part of the brain scans what is happening against what has happened before to try and answer the question, "Am I safe?"

If a threat is determined, the hippocampus alerts, "DANGER!": and Pathway 2 is decided upon by the thalamus. The amygdala takes over in a process known as the amygdala hijack, and a flood of hormones is urgently released into the body. Once this happens, our ability to access the slower thinking part of our brain becomes extremely limited (and in some cases shuts down completely so we can’t think logically).

Our potential for either a thoughtful or reflexive response is determined by our unconscious perception of safety, which depends upon our knowledge, memories, and experiences. In other words, our reactions are a result of both nature and nurture.

Side-by-side of two emojis - one a smiley face titled 'How it started' and two a brain exploding emoji titled 'How it's going'

When you get defensive, where do you feel it in your body? Maybe it’s a tight chest or flushed cheeks. Or perhaps the stomach flip flops or the head starts buzzing. Or, if you’re particularly fortunate, it could even be all of the above.

Pathway 2 is so quick that we are not even aware when we begin to feel defensive. First signs of such a response show up in the body, so it’s really important for us to know what particular feelings arise for each of us. Noticing these sensations is the key to recognizing what’s happening. The sooner we do, then the sooner we can change course and gain access to the thinking part of our brain once again.

If your life is at risk, by all means: run! But the reality in the modern world is that most of us get defensive when we’re not about to die. This reflexive response becomes a real problem in solving issues in relationships.


It is important to understand that the hormones associated with the amygdala hijack circulate in our bodies for anywhere from 20 minutes to a full hour – and if something or someone else escalates the situation, then even more flood our systems.

While we can’t stop this physiological reaction, we can recognize it for what it is and do our best to adjust. By quickly taking actions that will allow us to gain access to the thinking part of our brains, we can choose a much better response.

The first step is recognizing what’s happening – by noticing the rising feelings we’ve already mentioned. Then, we try to find a constructive way to respond. For example, sometimes the best thing we can do is to ask the person we’re interacting with if we can revisit this tomorrow. This will give your system time to reset so that you can think straight, and not think / say / do something you regret.


We don’t choose to be defensive, but we can work with it so we don’t stay in the state quite so long.

Understanding our biology can be a relief; we can recognize that sometimes our actions are less-than-rational because of the nature of the human mind. However, it does not absolve us of responsibility. In fact, this knowledge emboldens us with an opportunity to better see ourselves and the way we interact with the world.

Primed with both biology and lived history, it’s easy to see how conflict naturally arises and can be escalated by defensive reactions. But it’s also clear that it doesn’t need to be this way – we are empowered to resolve conflict.

A client shared with us this reflection after completing our online Dealing with Defensiveness course:

I thought I was going into this course to learn how to handle defensiveness in others, and I did! But I have learned so much more about myself and my own defensiveness. Here’s hoping that I can use it to develop, and in some cases, restore relationships that are so very important to me.

Let this work on your personal development spiral outward and into your home, workplace, community, and beyond. At Mediation Services Winnipeg we offer a myriad of educational resources online and in-person that focus on working with the potent space that is conflict.

We are more than our biology. With a little bit of effort we can work to accept responsibility and build deeper and more trusting relationships.

If you have questions,
please don’t hesitate to call.

1-204-925-3410

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