Logical vs Rational. The real reason people buy (and what it means for your business)
If I asked you why you brush your teeth every morning, what would you say?
Chances are, you’d give me the ‘sensible’ answer, “To keep them clean and healthy, so I don’t need fillings or get gum disease.” Or something along those lines.
That’s the logical response. It’s backed up by science, it’s what we were taught as kids, and it sounds like the right thing to say.
But the truth is, and it’s a point Rory Sutherland makes brilliantly in the book Alchemy (which if you haven’t read it’s a must!), most of us don’t brush our teeth because we’re lying awake at night fretting about plaque. We do it because we don’t want bad breath when we meet people. We want to be kissable, employable, and presentable.
That’s the rational reason. It’s less about long term dental health, and more about social survival.
And here’s why this is something to be aware of. When people make buying decisions, it’s usually the rational reasons (the emotional, social, subconscious ones) that drive the sale, not the perfectly logical ones.
So, what’s the difference?
The words logical and rational often get used interchangeably, but they’re not the same.
Logical decisions are based on facts, data, and reason. They’re the kind of choices you’d expect from someone weighing up the ‘sensible’ option. Such as that brushing your teeth prevents fillings and gum disease.
Rational decisions are about what actually makes sense in our messy, emotional, social lives. They’re about feelings, perceptions, and avoiding pain (social or otherwise). Brushing your teeth so you don’t gross out your partner with morning breath.
See the difference? Both decisions are perfectly defensible. But only one reflects how most of us behave in the real world.
Why this matters in business
As founders, we’re often told to sell using logic. To highlight features and benefits. To talk about price points, quality, and functionality.
And yes, those things matter. Customers want to know your skincare is made with natural ingredients, or that your bag is handmade, or that your product lasts longer.
But here’s the uncomfortable truth, logic rarely closes the sale. If fact, I’d say it very rarely does.
What actually tips people over the edge is the rational side, how your product makes them feel, what story it lets them tell themselves, or how it shapes the way other people see them…perception is super important.
Think about it.
Nobody pays £4 for a Starbucks latte just for caffeine. They pay for the feeling of a treat, a brand that signals something, and that moment of comfort in their morning routine.
Nobody buys luxury candles because they need light. They buy them because it makes their home feel cosy, because it impresses guests, because it’s a little everyday indulgence.
Nobody spends £120 on branded trainers just to protect their feet. They’re buying status, confidence, and a sense of identity.
In all of these cases, the logical reason is there in the background, but the rational reason is what really drives the purchase.
The ‘smelly breath’ question for your business
The toothbrush story is a brilliant reminder that the reason people buy is often very different from the reason they say they buy.
So here’s a question to ask yourself when you’re thinking about your products, your marketing, or even your customer emails,
What’s the ‘smelly breath’ reason my customers are really buying this?
Because whatever the logical reason is, sustainability, price, quality, durability, there’s almost always a more emotional, human, sometimes slightly irrational reason sitting underneath it.
A few examples
Let’s take a look at how this plays out in different industries.
Handmade jewellery
Logical. It’s crafted from high quality, long lasting materials.
Rational. You get to tell your friends “oh, it’s from this small independent maker,” which makes you feel unique and special.
Online courses
Logical. You’ll learn new skills and grow your business.
Rational. You’ll finally feel like you’re moving forward instead of stuck. You’ll gain confidence and be able to introduce yourself as someone who knows their stuff.
How to apply this to your marketing
So, how do you use this insight to actually sell more?
Here are some practical ways.
Write copy that speaks to feelings, not just facts
Don’t just say “our moisturiser hydrates for 24 hours.” Add, “so your skin feels soft, glowy, and selfie ready all day.”Highlight social signals
Show how your product helps customers look good, fit in, or stand out, depending on what they want.Tell a story
People buy into narratives. Frame your product as part of a bigger lifestyle or identity.Dig deeper in your customer research
When talking to customers, don’t stop at the first “why.” Keep asking why that matters until you uncover the deeper, more human reason.
Bringing it all together
At the end of the day, humans are messy. We don’t make decisions based on spreadsheets and logic charts, at least, not most of the time. We make decisions based on what feels right, what feels safe, what makes us look good, or what helps us avoid ‘smelly breath’ moments.
So as a small business owner, your job isn’t just to prove your product makes sense on paper. It’s to connect with the real, human, often irrational motivations your customers have.
Because when you can combine the logical with the rational, giving people a good reason to buy, and a good story to tell themselves about buying, that’s when your marketing really starts to land.