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Personality Tests Are Useful—But They Don’t Tell the Whole Story: What Neuroscience Adds to the Picture


Why understanding your Head, Heart, and Gut is the missing link between personality profiles and personal growth.



In coaching and leadership development, psychometric tests have become something of a gold standard. Whether it’s DISC, MBTI, Hogan, EQ-i 2.0, or the Enneagram, these tools promise insights into who we are, how we think, how we behave, and what we can improve.


And often, they deliver exactly that.


They’re structured, researched, and give people something tangible. A profile. A pattern. A report that says, “This is how you operate.” That’s incredibly reassuring, especially in professional environments where we long to make the invisible visible. In team settings, they can even become a new language—“Ah, that’s just my high D talking,” or “She’s a classic Type 6.”


They’re powerful mirrors. But a mirror doesn’t create movement. It reflects what is, not what’s needed next.”

The question that keeps coming up for me and many of my coaching colleagues:

Do these tools truly lead to sustainable behaviour change, or do they mostly describe it? Does the person change, or just nod, acknowledge, and move on?


And most importantly:

Do these tools go deep enough to shift the actual source of our behaviours?

Let me say upfront: these tools are not wrong or outdated—they’re incredibly valuable. I’ve used many of them myself in coaching. And for those of us who’ve used DISC, MBTI, Hogan or Enneagram for years—this isn’t about throwing them out. It’s about integrating a biological lens that reveals what those patterns are trying to protect or compensate for.”


After coaching thousands of professionals across industries, I’ve come to see both the beauty and the blind spots of these assessments. They help us see ourselves more clearly, yes. But do they help us change?


What Personality Tests Offer—And What They Miss

Most well-known assessments are grounded in decades of behavioural research. They measure how we think, feel, and act under different circumstances, often through the lens of preferences or traits. DISC, for instance, tells us if we’re more dominant, influential, stable, or conscientious. The MBTI categorises individuals into 16 types based on their tendencies in perception and judgment. Hogan identifies leadership risks. The Enneagram reveals deep emotional strategies.


Let’s begin with what psychometric tools do well:

  • They create structure. Most are built on well-researched behavioural or personality models. They help people organise what might otherwise feel like a swirl of thoughts and emotions.

  • They offer a language. Terms like “introvert,” “thinking preference,” or “influencer style” provide clients and teams with a way to discuss themselves and others without judgment.

  • They boost self-awareness. Even the act of answering questions and reading the results can prompt reflection.

  • They support team understanding. In organisational contexts, they can help improve dynamics by highlighting diversity in thinking and communication.

From a coaching perspective, this makes them an excellent starting point. They’re a way in. As a coach, I’ve used these tools. They open doors. They make the invisible visible.


However, what I’ve found—over and over—is that once the excitement of the results wears off, many clients return to the same patterns, frustrations, and reactive behaviours. 

Why? They don’t say how to move forward; they identify behaviours, but not the systems behind them.



A Real-Life Example: The CFO Who Didn’t Believe Me


Let me illustrate with a real experience.


I was once brought in to coach a CFO who was considered brilliant by many in the company but also difficult. During our intake session, which lasted just over an hour, I shared my observations with him. I reflected on his decision-making process, where he was disconnected from others, how his internal drivers were likely influencing his decisions, and what he would need to shift to become more effective.


His reaction?

His response was respectful but sceptical.

He said, “Well, you’ve never been a CFO, have you? So I’m not sure how valid your feedback is. It feels… too personal.”


Fair enough. I hadn’t been a CFO. But I had coached dozens of senior executives, and I was drawing on years of neuroscience-informed behavioural reading.


Still, he dismissed the feedback. 


Three months later, the organisation decided on the company's approach, and all the senior leaders and the full executive board completed a well-known psychometric battery.

And, surprisingly, though perhaps not, his report said exactly what I had told him, word for word, in some parts.


Suddenly, those insights were accepted. He believed them because the data came “from a tool,” not a human being in front of him.

This is the paradox of many psychometric tests. They are believed because they feel neutral. However, neutrality doesn't equate to depth or transformational power.



Description ≠ Transformation


Let’s be precise here.


Psychometric tools describe what we do. They map tendencies. They show us behavioural outputs. But they usually don’t:

  • Explain where those behaviours are coming from in the body or nervous system

  • Indicate which internal “system” is dominating our choices

  • Which belief systems or traumas could be responsible for the behaviour

  • Or tell us how to train a new response in moments of stress, conflict, or uncertainty


This is especially important in coaching. Because when people come to us, they’re not just looking for understanding. They want a change in how they speak, lead, decide, act, or relate.


So if we tell someone, “You have a low extraversion score,” or “You’re more conscientious than open to change,” what next? We’ve provided a mirror. But have we provided a method?


This is where many coaches—and clients—get stuck. The psychometric assessment has labelled the pattern. But the human being still doesn’t know what to do with it. Or they think, “Well, this is just how I’m wired.”



Patterns Are Not Permanent


Another limitation of many tests is how they reinforce a fixed identity.


You’re a Type 5. A Red/Yellow. An INTJ. A high C.


It’s tempting to believe that’s who we are.


Recently, a MCC coach with over 20 years of experience told me, Chris, that it's a normal reaction. You are a Type 7, 8, and 1 Enneagram type, so it makes sense that you are like that and do those things. So I am a 7,8, and 1, am I?


It’s tempting to believe that’s who we are.


But the truth is more fluid.


Who we are in one environment is often not who we are in another. Stress shifts us. Success shifts us. So does trauma, conflict, or even a deep conversation.


Even the way we fill out a psychometric test depends on the state we’re in at the time. Are we feeling confident? Defensive? Ambitious? Exhausted? That state colours our answers—yet we treat the results as absolute truths.


In that sense, psychometrics are more like photographs than X-rays. They capture a surface image of a moment but may miss the deeper forces at play.

They can help us understand where we are. But they often don’t explain why we’re stuck—or how to activate the part of us that could get us unstuck.



The Comfort of the Known

Let’s also acknowledge that these tools are deeply popular because they offer comfort. They fit into PowerPoint slides. They produce nice-looking charts. They have decades of research behind them.


However, sometimes they comfort us at the expense of real challenges. They give us stories about ourselves rather than activating the curiosity and courage required for true growth.

In that sense, they are often better suited for describing teams than transforming individuals.

Most assessments stop at awareness.


They mirror back behaviour.

But they don’t address the biological and emotional systems behind the behaviour. They don’t show us which part of ourselves is blocking change, and they don’t offer tools to train that part into alignment.


And in my coaching experience, that’s precisely the challenge:

Once people know their pattern, they need a way to shift it. And that’s where we need to go deeper—into the biology, the emotional memory, and the systems of inner decision-making.



A Gentle Reframe

So, am I saying psychometrics have no place in coaching? Not at all.

They can be excellent diagnostic tools. They open awareness. They reveal patterns. They provide clients with a language and coaches with a structure to initiate a conversation.


But we must see them for what they are:

  • Maps, not methods

  • Descriptions, not prescriptions

  • Starting points, not solutions


But if we want to help that person move—to shift behaviour, to train a new pattern, to become more whole—we need something more than a behavioural cluster or a type.


As coaches and leaders, we often meet clients at that very edge:They’ve just completed their DISC profile, MBTI report, or Enneagram type. They have more awareness. They are aware of how they tend to behave.


But here’s the real question:

Do they know who inside them is driving those behaviours—and how actually to shift them?

We need to work with the part of the system where the behaviour is created in the first place.

That’s where the 3 Brains Intelligence model begins.



Who’s Really in Charge? The Science Behind the 3 Brains

It might sound metaphorical at first, but it’s not:

We don’t have just one brain. We have three.

Neuroscience now confirms that in addition to the Head Brain, we have two other fully functional, decision-making neural networks:

  • The Heart Brain (cardiac neural network)

  • The Gut Brain (enteric nervous system)


Each of these brains:

  • Has its own neural pathways

  • Stores emotional memory

  • Can learn, process, and influence our behaviour


And perhaps most importantly:

Each brain has its own agenda for keeping us safe, successful, and aligned.

The 3 Brains in Brief:

  • 🧠 Head Brain: Thinks, analyses, doubts, plans, strategises

  • ❤️ Heart Brain: Feels, connects, values, remembers emotional truth

  • 🧍‍♂️ Gut Brain: Acts, protects, risks, and reacts from instinct and survival


We all have all three.

But depending on our life experience, upbringing, trauma, or environment, one often dominates, and another goes more dormant.


That imbalance isn’t a personality trait. It’s a system-level issue.

And most behavioural struggles—procrastination, indecision, burnout, relationship conflict—can be traced back to this internal misalignment.


And most importantly:
Each of these brains can be trained.


From Insight to Internal Leadership

The 3 Brains Preference Assessment doesn’t try to define who you are.


Instead, it asks a more powerful, practical question:

Which brain is running your life—and which one needs to be trained to get you where you want to go?


This is the crucial difference.

It’s not about your type. It’s about your internal leadership team—and whether your logic, values, and instincts are working with each other or against each other.



The Science of Blocked Brains


Let’s take a few examples you may recognise:

  • A leader who overanalyses but rarely makes bold decisions? Their Head Brain dominates while their Gut Brain is suppressed.

  • A talented manager who avoids emotional conversations with their team? Their Heart Brain may be silent due to past experiences.

  • A reactive team member who jumps into action before thinking it through? Their Gut is on overdrive, while their Head is disengaged.


In classic psychometrics, these people might be labelled:

  • “Low conscientiousness”

  • “Low empathy”

  • “High impulsivity”


But these are just labels on the surface.

The 3 Brains model goes deeper:

  • Which brain is actually reacting?

  • Which brain is missing from the inner table?

  • What would happen if that brain's voice were heard?

  • And how can we train the silent brain to rejoin the system?


Where most assessments ask, What’s your personality?


The 3 Brains Intelligence Preference Assessment asks,

Which of your three internal brains is steering your decisions—and which one needs support?


A Tool That Points to the Source


The 3 Brains Preference Assessment is short—just a few minutes. But it gives a clear, targeted outcome:

  • It identifies which brain is dominant in decision-making

  • It shows which brain is underused or overridden

  • What does that combination mean for your daily decisions and struggles


In practice, this means you’re not told:


“Show more of your Type 4”, “Express more of your Green side”  or “Show more assertiveness.”


You’re shown:

“Your Head had the highest score, and your Gut Brain has the lowest score, meaning you like to think before you speak and when you vocalise, know what you verbalise is correct, and as your Gut brain has the lowest score you will not follow easily your instinctive feelings about what is right or wrong without proof. So, we have to work on that: to start learning when you can trust your gut feeling and when you cannot. That’s why you hesitate when it’s time to speak your truth or take a risk.”


And then:

You’re given techniques, exercises and tools to train that brain, just like you’d train a muscle or a skill.

When you were born and a baby, you were totally capable of expressing (in all ways 😁)  your needs and gut feelings. 

And that matters. Because change doesn’t happen in the mind alone; it happens in the neural circuitry of the body.



A Practical Advantage: Simplicity, Clarity, Speed


Many psychometric reports range from 20 to 40 pages. They contain graphs, typologies, scores, and suggestions. That’s helpful in a corporate learning context—but often overwhelming for individual coaching.


The 3 Brains Intelligence Preference Assessment offers something simpler:

  • A one-page result

  • A clear hierarchy of which brain dominates your decision-making

  • A spotlight on which brain is under-engaged

  • A focused interpretation that points immediately to growth areas


This is not superficial. It’s targeted.

And as we say in neuroscience, our 3 brains love clarity.


Let’s say:

  • You want to become more assertive at work. That’s a Gut Brain issue.

  • You want to make better, data-driven decisions. That’s the Head Brain.

  • You want to build deeper relationships or rebuild trust. You’ll need your Heart Brain on board.


Rather than labelling you as an introvert, thinker, or “green,” the 3 Brains model identifies the internal brain system that is overactive, underdeveloped, or ignored—and provides practices to train the missing intelligence.


In just one session, a client can shift from confusion (“Why do I keep sabotaging myself?”) to clarity (“Ah, my Heart Brain is blocking my Gut — no wonder I can’t stay vulnerable”).

From there, we begin the real work, not of becoming someone new, but of integrating what’s been there all along.


From Assessment to Action: How the 3 Brains Model Creates Transformation


Once we identify the dominant and silent brains, we don’t stop at awareness.


We begin training the 3 Brains.


In my coaching work, this might include:

  • Exercises to re-engage the Heart Brain through listening, emotional attunement, memory reconnection or removing emotion-limited beliefs 

  • Tools to activate the Gut Brain—learning to feel the courage to speak, decide, and act, overcoming highly impactful experiences (what not the same as traditional Psychology defined trauma, where we think of strong emotional negative, physical or emotional experiences but all the experiences that taught us a coping mechanism to expand the negativity. And that coping mechanism is still running the show) 

  • Practices to bring in the Head Brain for clients who need to slow down, plan, or challenge impulsivity


Each of these is grounded in neuroscience, not personality theory.


We're not trying to change who someone is—we’re helping them integrate what’s already inside them, but has gone dormant, blocked, or neglected.

This also makes the approach trauma-sensitive.

We recognise that some brains go silent for a reason—often to protect the system.


However, that silence comes at a cost: misalignment, stagnation, and exhaustion.


By reawakening all three brains and bringing them into collaboration, we move toward what I call whole-brain leadership, where your logic, values, and intuition work together, not in conflict.



Returning to the CFO Example


Let me revisit the experience I had and the learning which Brain I should have talked more from. 


When I first shared my intuitive and neuroscience-based reading of a CFO’s inner dynamics, he dismissed it. He couldn’t relate—because, as he said, I wasn’t a CFO myself. And I did not use my Head Brain enough in the feedback.


But when he filled out a psychometric test, which echoed the same insights in a different language, he accepted them. The difference? He trusted the test because it reflected his own input, which was based on logic and analysis.


That taught me something powerful:

People are more willing to believe their behaviours when they recognise them in themselves.

That’s precisely what the 3 Brains Assessment enables:

  • It’s short enough not to intimidate

  • Personal enough to feel relevant

  • Precise enough to catalyse change


The CFO didn’t need 30 pages. He needed a mirror that felt neutral and used his language, and still pointed him toward his own blocks. 

The funny part is that after this assessment, he called me to ask me if I would like to be his coach. He never admitted it, but I had a strong suspicion that the HR Director who asked me to coach him the first time was behind this 😆.



The Future of Coaching Tools: From Personality to Biology


So, where does this leave us?


Psychometric tests aren’t wrong. They’re just incomplete. I still use other assessments when they’re helpful.

They show us patterns. They reflect behaviour. They offer useful language. I still appreciate the structure they provide.


But I now start with one core belief:

If we want to change behaviour, we need to understand not just what people do but which part of their nervous system is doing it.
Change happens when we train the part of us that’s been missing from the conversation—when we reawaken the silent brain and create alignment between Head, Heart, and Gut.

That’s the promise of the 3 Brains Intelligence model:

  • Not just about understanding. But alignment.

  • From fragmented decision-making to integrated leadership

  • From stuck behaviour to systemic clarity

  • From intellectual insight to embodied transformation

  • Not just about understanding or preference. It’s about an embodied transformation

  • Not just about types. But training the right brain to take action, connect, lead, decide, and grow.


Because awareness is powerful, but when the Head, Heart, and Gut are in dialogue, transformation is not just possible—it’s natural.


Are you curious about which brain is running your life right now?

If you never did the 3 Brains Intelligence Preference Assessment, do it here for free: https://www.3brainsintelligence.com/3-brains-preference-dominance-assesment



If you'd like to become a master in 3 Brains coaching from September onwards, we have some great opportunities.








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