Why We’re Less Rational Than We Think

The Hidden Driver of Our Decisions: Why We’re Less Rational Than We Think

We consider ourselves rational beings, carefully weighing our options before making decisions. We pride ourselves on analysing, planning, and executing thoughtful choices.

But what if most of our daily decisions aren’t made by our logical, thinking brains? What if a more primitive part of our neural architecture is genuinely in charge?

The Triune Brain Model: A Blueprint for Decision-Making

Let’s explore the “triune brain” model to understand this phenomenon. While somewhat simplified, it provides valuable insights into how our brain functions. This model divides the brain into three distinct layers:

  1. The Reptilian Brain: The oldest part of our brain, comprising the brain stem and cerebellum, governs survival instincts, habits, and automatic behaviours. This part takes over when we’re on autopilot—driving the same route to work, reflexively reaching for our phone, or grabbing that afternoon snack at precisely 3 PM.
  2. The Limbic System: Known as the emotional brain, it processes feelings, social bonds, and memories, influencing how we connect with others and respond emotionally.
  3. The Neocortex is the youngest and most advanced layer, responsible for logic, reasoning, and conscious thought. This is where we believe decision-making occurs, but it often justifies decisions already made unconsciously.

The Illusion of Conscious Control

Here’s the startling truth: research suggests that up to 95% of our decisions are driven by unconscious processes, primarily governed by the reptilian brain. Think about your morning routine.

Did you consciously decide the sequence of brushing your teeth or which hand to use to lift your coffee mug? Likely not. These decisions happen on autopilot, saving cognitive resources for more complex tasks.

This automatic system was essential for our ancestors, enabling them to react swiftly to threats and conserve mental energy. However, in today’s world, this same system can make changing behaviors—and breaking bad habits—incredibly challenging.

The Habit Loops That Bind Us

The reptilian brain thrives on efficiency, forming habits through well-worn neural pathways. Imagine these pathways as trails in a forest. Each time you repeat a behaviour, the trail becomes more defined, making it your brain’s default route. This is why habits feel so automatic—and why creating new ones can feel like blazing a new trail in dense woods.

Breaking the Cycle

Understanding how habit loops work is the first step toward change. The typical loop involves:

  • Cue: A trigger that initiates the behaviour.
  • Routine: The behavior itself.
  • Reward: The payoff that reinforces the habit.

You must disrupt one or more elements of this loop to change a habit. But doing so isn’t easy; it requires intentional effort and strategies that align with your brain’s natural tendencies.

How to Work With, Not Against, Your Brain

Changing behaviour starts with understanding the brain’s preferences for efficiency and predictability. Here are actionable steps to reshape your habits:

  1. Leverage Environmental Triggers: Set up cues that encourage desired behaviours. For instance, if you want to exercise in the morning, lay out your workout clothes the night before.
  2. Start Small: The reptilian brain resists drastic changes but adapts to incremental ones. If you’re trying to drink more water, start with an extra glass a day.
  3. Repetition is key. Consistently repeating a new behavior strengthens neural pathways, and over time, it becomes second nature.
  4. Be Compassionate With Yourself: Resistance to change is hardwired. Acknowledge setbacks without judgment and focus on progress, not perfection.
  5. Use Positive Reinforcement: Celebrate small wins to associate the new habit with pleasure and encourage its continuation.

Why Understanding This Matters

At first glance, realizing how much of our behaviour is governed by the primitive reptilian brain can seem discouraging. However, this knowledge is empowering. By acknowledging its influence, we can design our environments and routines to align with our goals rather than battling against ingrained tendencies.

Instead of trying to overpower your automatic responses, aim to guide them. Craft environments that make healthy habits easier to adopt and poor habits harder to maintain. With patience and consistency, you can reprogram your brain’s default settings.

Final Thoughts

Our reptilian brain isn’t our enemy—it’s a powerful ally when harnessed correctly. The key is approaching behaviour change with strategy, compassion, and persistence. By reshaping our automatic behaviours, we can make meaningful, lasting changes that align with our long-term aspirations.

So, the next time you find yourself operating on autopilot, take a moment to reflect: is your reptilian brain serving your goals or holding you back? The choice to guide it—rather than fight it—is the first step toward unlocking your true potential.