You Don't Have A Lizard Brain - And How The Alternative Supports Better Decision-Making

You have more agency than you realise

1. A teachable moment

A couple of months ago, I was in a gorgeous Georgian-style room in Salisbury, gazing at an incredible view of Salisbury Cathedral.

It was the third module session for the Diploma in Art-based Coaching (led by Anna Sheather) I’m currently studying.

The session combined teaching us about trauma-informed coaching (delivered by a guest expert) and using art-based coaching within trauma-related conversations.

I keenly took it all in as it’s a subject close to my heart.

But then it happened.

The guest expert mentioned the ‘primitive reptilian part of the brain’ kicking in help us survive in stressful situations.

Ummm…I thought.

But that’s not true.

We don’t have a primitive, reptilian brain helping us survive! I started to feel uneasy and shifted in my seat.

Now, I’ve come across the lizard or reptilian brain model hundreds of times over the years. It pops up in standard media articles as well as some psychology textbooks (still).

This makes sense since the concepts of the cold, instinctive mind (lizard you) versus the emotional, erratic mind (mammalian you) have been part of western society since Plato 2,000 years ago.¹

The only snag?

It’s wrong.

Photo by NARESH JOSHI on Unsplash

2. Only lizards have lizard brains

Neuroscientists and evolutionary biologists have known for decades that the human brain didn’t evolve over time like an onion, based on 3 layered parts.

This Triune Brain theory (popularised by Paul MacLean and Carl Sagan in the 1970s) describes these three parts and their suspected functions - the lizard brain (survival instinct), limbic system (emotional), and neocortex (rational)².

Fortunately, the brain doesn’t work like this.

The brain didn’t evolve over time in successive stages. Neural regions are generally common across all vertebrates.

They just differ in development time, and how they are structured and adapted to the relevant function e.g. a nose versus a trunk.

The genetic foundations across species are often common, and develop against a common brain-manufacturing plan.

It’s the timing in each species that drives the difference in how these brain regions look, integrate and function.

Back to the classroom.

After feeling super itchy for a while, and questioning whether I should raise my hand and tell the expert they weren’t quite right, I knew I should.

I couldn’t let this lizard brain thing perpetuate across the group.

Photo by National Cancer Institute on Unsplash

3. The adaptive brain

I shyly raised my hand and quietly stated that the lizard/reptilian brain theory wasn’t accurate.

The brain works in a more predictive and adaptive way according to modern neuroscience.

After an uneasy sense across the room, they asked me to share the latest research with the group. Yikes.

Where’s the lizard brain when you need it? (lol).

I talked about the Adaptive Brain theory, and how our brain changes our body budget, based on internal and external environment data, to prepare for predicted outcomes.

This helps us respond to situations more adaptively versus waiting for confirmation.

Neuroscientist and teacher Dr Sarah McKay describes these concepts beautifully in her rethinking the reptilian brain article³.

She summarises the Adaptive Brain theory by Steffen, Hedges and Matheson (2022) and Lisa Feldman Barratt’s Theory of Constructed Emotion in an accessible way.

4. How to make better decisions

So does this all matter? It does.

We should understand how our brains function, but also how they don’t.

You aren’t a slave to a cold, reptilian, instinctive lizard in certain circumstances.

Your emotions aren’t always irrational and your thoughts aren’t always rational or logical. You aren’t at the mercy of raw instinct. You have agency.

During my time in investment banks, it made me laugh when people talked about how rational and logical the stock markets were. You HAVE got to be kidding me?

The stock markets are often based on gossip and getting spooked!

No one wants to be last or make a loss (FOMO anyone?).

They get wind of something sketchy and make a whole bunch of decisions based on that, even if the data might indicate something else.

Their brains are busy predicting outcomes and they crack on with their deals to protect or execute their strategies.

Sometimes that pays off. Sometimes it doesn’t.

There is only so many times the prediction lines up beautifully with reality.

So instead of classifying emotional decisions or logical decisions, and if they are good or bad, do this instead.

Switch decision-making to whether your predictions are helpful or unhelpful in the current situation.

Ask yourself these questions when a decision arises:

• How does your body feel?

• What emotions do you notice?

• What action gets you where you want to go?

• What action no longer serves you?

• What action should you take right now?

• Should you do nothing?

You aren’t just blindly responding to something.

You’re noticing what your brain and body are trying to tell you.

You get to determine the best course of action.

And based on the results, your predictions will be reinforced or updated for next time.

So next time you hear about the lizard brain, point them to this update and challenge their assumptions.

You have more agency than you realise.

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Let me know what you're keen to learn or talk about in the comments below or on chat.

This is your space too, so let's enjoy it together.

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Take care,

Sabrina Ahmed

Burnout Coach | Neuroscientist | Art-based Practitioner

1. Seven and a Half Lessons About the Brain (Lisa Feldman Barratt)

2. Frontiers | The Brain Is Adaptive Not Triune: How the Brain Responds to Threat, Challenge, and Change (frontiersin.org)

3. Rethinking the reptilian brain (Dr Sarah McKay)