Train Your Reality

How Your Brain Filters Reality: The Power of the Reticular Activating System

What if the things you notice most aren’t coincidences—but reflections of what your mind has been trained to see?

It’s like playing the game “Spotto” with the kids or buying a red car, and you suddenly see yellow and red cars everywhere? Or maybe you’ve been learning a new word and suddenly hear it pop up in conversations, podcasts, or on TV.

That’s not coincidence.

That’s your brain’s filter at work.

It’s called the Reticular Activating System, or RAS for short—and once you understand how it works, you start to realise just how much influence it has on the way you see, experience, and interpret the world around you.

The RAS is the brain’s internal spotlight operator. It decides what gets your attention and what fades quietly into the background. It shapes your perception—and your perception shapes your reality.

And here’s the key insight: whatever you focus on expands.

Your Brain’s Filter: The RAS Explained

The Reticular Activating System sits in your brainstem, a small but mighty bundle of neurons with an enormous job. It processes the flood of sensory information your brain receives every second and decides what’s relevant, useful, or worth noticing.

Think of it as the bouncer at the nightclub of your mind. Thousands of sounds, thoughts, and sensations are trying to get in, but the RAS decides who makes it past the velvet rope.

As you’re reading these words right now, you're probably really focussed on understanding them. But you’re probably not consciously noticing the hum of the fridge, the faint traffic outside, or the way your feet feel against the floor.

That’s your RAS quietly doing its job, filtering out the noise so you can focus on what matters most in this moment.

Why Your Focus Shapes Your Reality.

Here’s where it gets fascinating.

Your RAS isn’t just filtering for survival; it’s filtering for meaning. It pays special attention to the things your brain believes are important.

If you’ve just had a baby, you suddenly notice every pram and parenting podcast.
If you’ve started looking for a new home, every “For Sale” sign seems to glow.
If you’ve recently been through a tough breakup, songs about love seem to follow you everywhere.

Your external world hasn’t changed.

Your internal filter has.

The RAS acts much like the algorithm behind your social media feed. Whatever you engage with most determines what you see more of. If you linger on posts about frustration or fear, your feed fills with more of the same. If you engage with positivity, purpose, or growth, you’ll start seeing those patterns emerge everywhere.

In neuroscience, this links closely with confirmation bias, the tendency to notice information that confirms what we already believe.

If you believe people are unkind, your RAS will highlight rudeness, rejection, and judgment.
If you believe people are fundamentally good, you’ll start spotting moments of generosity, empathy, and connection.

In both cases, your brain is proving itself right.

That’s why understanding your RAS is so powerful—because it means you can train it.

A Quick Look at the Science

The RAS was first identified in the 1940s by scientists Giuseppe Moruzzi and Horace Magoun, who discovered that stimulating this region could wake animals up, while cutting it off sent them into deep sleep.

Their work showed that the RAS regulates arousal—not just in terms of sleep and wakefulness, but also alertness, motivation, and focus.

Modern neuroscience has since expanded this understanding. Brain imaging studies show that when people set clear goals, practice gratitude, or visualise positive outcomes, the RAS literally changes its activity patterns. It begins to prioritise information that aligns with those intentions.

That’s why tools like gratitude journaling, affirmations, or vision boards aren’t just motivational—they’re neurological. They’re simple ways of giving your RAS new instructions:

“This is what matters. Show me more of this.”

Training Your RAS to Work For You

Your RAS is neutral. It doesn’t care whether it’s filtering for fear or possibility—it simply follows the directions you give it.

If your self-talk is full of “I’m not good enough” or “things never work out for me,” your RAS will quietly gather evidence to support that. You’ll notice every setback, every awkward silence, every small failure.

But if you start to intentionally shift your focus—toward progress, kindness, learning, or gratitude—your RAS begins to gather different evidence.

Here are a few practical ways to start training this system:

1. Set Clear Intentions

Your RAS loves specificity.
Instead of saying, “I want to be healthier,” try: “I’ll walk 20 minutes every morning.”
Your brain now knows what to look for—time in your schedule, routes, supportive habits.

2. Visualise Success

Olympic athletes don’t just train their bodies—they train their brains.
By vividly imagining the race, the movement, or the goal, they’re priming their RAS to recognise the real-world cues that lead to success.

3. Write It Down

Writing your goals or gratitude each day is one of the simplest and most effective RAS “hacks.”
When you write something down, your brain treats it as a directive—“This matters.”

4. Ask Powerful Questions

Your RAS loves a question.
Try asking yourself in the morning:
“What do I want to notice today?”
“What opportunities might show up?”
Your brain will quietly spend the day looking for answers.

5. Reframe What You See

When something stressful happens, pause and ask:
“What else could this mean?”
This one simple question disrupts the automatic filter of negativity and invites your RAS to find a broader, more balanced perspective.

The Stories We Tell Ourselves

I once worked with someone who believed she “just attracted toxic workplaces.” Everywhere she went, she found the same patterns—criticism, gossip, burnout.

When we started exploring it, she realised her RAS was trained to look for negativity. Every sigh, every frown, every frustrated tone became evidence of dysfunction.

As she began intentionally searching for moments of humour, cooperation, and encouragement, something shifted. The workplaces didn’t suddenly become perfect—but her experience of them did. And that changed how she showed up, interacted, and led.

Different focus.

Different reality.

Your RAS and the World Around You

It’s not just individuals who are affected by what they tune into—whole groups, organisations, and even societies are shaped by what their collective RAS is trained to notice.

Think about the impact of constant exposure to negativity in the media. If all we consume is fear, outrage, and division, our brains start believing the world is hostile and unsafe.

But if we intentionally seek out stories of kindness, innovation, and resilience, we see evidence of a world that is creative, caring, and full of potential.

Neither version is more true—but one creates more hope, connection, and action.

The Happiness Hack: Prime Your RAS

Here’s a simple, powerful way to put this into practice.

Each morning, take 60 seconds to set your mental filter. Ask yourself:

“What’s one thing I want to notice today?”
(It could be kindness, calm, confidence, or joy.)

“What’s one question I want my brain to answer?”
(Maybe, “What am I grateful for?” or “Where can I make progress today?”)

Then let your RAS quietly do the work.

You’ll be surprised how quickly you start noticing things you used to overlook.

The world doesn’t change first—you do. And when you shift your focus, your experience of the world begins to transform with it.

Understanding your Reticular Activating System isn’t just about neuroscience—it’s about empowerment. It reminds us that we are not passive observers of our world; we are active participants in shaping what we see, feel, and experience.

When you train your RAS intentionally, you begin to notice the opportunities, connections, and beauty that were always there—you just hadn’t tuned in yet.

And that’s where lasting happiness starts: not with changing everything around you, but with learning to see what’s already working.

Want to go deeper?

Listen to The Happiness Hack with Tim Coulson—the podcast where science meets everyday wellbeing—and explore how small mindset shifts can transform the way you experience life.

Or, if you’re ready to apply these principles personally, book a session with me at tim-coulson.com.

Because happiness isn’t about having it all together—it’s about building something better, one thought, one habit, one moment at a time.