10 Cognitive Biases & What They’ll Do to Your Marketing

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Let me tell you about the worst apartment I ever rented.

Four stories up. No elevator. No plug-in for my car (which, by the way, was essential when it regularly hit –30°C). No air conditioning either—great for when it hit +30°C almost every day in summer. 

It was, objectively, a terrible decision. But it had exposed brick. And vintage radiators. Big main character energy. 

So I signed the lease without hesitation.

That was a textbook case of the affect heuristic. Basically, a fancy way of saying my brain latched onto how the place felt and tossed logic out the single-pane, drafty window. My emotional reaction overruled everything else.

We all do this. Constantly.

Because while we like to believe we’re logical, rational decision-makers, the truth is our brains are running on shortcuts. 

And this post? It’s all about how to market your business with those quirks (aka cognitive biases) in mind.

WTF Are Cognitive Biases?

Buying the skincare set because the packaging said “complete routine.”
Picking the second-most-expensive bottle of wine because it felt fancy, but not too fancy.
Trusting a stranger at a party just because they’re from your hometown.

None of those are “rational” decisions. They’re mental shortcuts.

That’s what cognitive biases are: mental patterns that help us make fast decisions, even when they don’t totally make sense.

We like to think we’re being rational. But most of the time, we’re reacting to what feels right, what looks familiar, or what’s easiest to process in the moment. These little quirks show up everywhere. From buying candles we don’t need to signing a lease for an apartment with ✨vibes✨ and no A/C.

And yes, they show up in how people read, click, book, and buy from your brand, too.

10 Cognitive Biases to Use (Lovingly) in Your Marketing

You’re not tricking people. You’re speaking their brain’s language.

1. Affect Heuristic → Lead with Storytelling

Affect Heuristic is when your brain makes a snap decision based on how something feels, not whether it actually makes sense. (See also: signing a lease because of exposed brick.) Because people don’t make decisions based on logic. They decide based on feeling, then back it up with logic afterward.

The copy strategy to pair this cognitive bias with? Storytelling.

Stories trigger emotion fast and let readers see themselves in the experience. So, open your about page with a mini-story that mirrors your reader’s own situation. Show them you get it—emotion first, explanation second.

2. Choice Overload → Cut the Options

Too many options lead to no decision at all. Your brain short-circuits, your cursor hovers, and suddenly you’re closing the tab before you clicked ‘buy’. When your reader has to stop and think about what’s “best,” they often choose nothing at all. 

The copy strategy to pair this cognitive bias with? Limiting Options.

The fewer decisions your reader has to make, the more likely they are to make one. So, highlight 2–3 core offers and pair them with short, clear labels to help readers choose fast.

3. Self-Generation Effect → Ask Rhetorical Questions

Self-Generation Effect says our brains remember things better when we come up with the answer ourselves, even if we’re just thinking it in our head. Your reader? They’re more likely to absorb and remember your message when their brain feels like it “discovered” it.

The copy strategy to pair this cognitive bias with? Rhetorical Questions.

Asking a question gets your reader actively thinking, so the idea sticks harder because they connected the dots. Try asking a rhetorical question right before your call-to-action and make the button the obvious answer. 

4. In-Group Bias → Pick a Common Enemy

We naturally trust people who feel like part of our crew. And that trust triples when we’ve got a mutual eye-roll going. When your audience sees you as someone who gets it, they’re more likely to stick around. Shared values = instant connection.

The copy strategy to pair this cognitive bias with? Common Enemy.

Take a stand on something your audience is tired of, like a tool, a strategy, or a frustration, shows that you’re “in” with them by calling out what you’re against and framing your offer as the alternative solution. Wondering what our common enemy is? Slimy, sleazy sales tactics that give us the ick.

5. Bundling Bias → Offer Add-Ons

When a core offer comes with extras, it feels more valuable and complete. Our brains love a “whole package,” even if we came there for one part. Bundled offers make decisions feel easier. Your reader doesn’t have to figure out what they need—they just see it laid out and know it’s all there.

The copy strategy to pair this cognitive bias with? Curated Add-Ons.

Layer in optional extras that make your main offer feel more useful, personalized, or luxurious. Think about your checkout page, sales flow, or products that just make sense together (like my Blogging Bundle!)

6. Bye-Now Effect → Drop it in the PS

We pay extra attention to whatever comes right before we leave…even if we just skimmed everything else. Your reader might scroll past 90% of your email, but that last little “P.S.” line? That’s where they’re primed to make a decision.

The copy strategy to pair this cognitive bias with? Adding a P.S.

Add a quick, final line that lands just before someone clicks out. It’s the last thing they see and often the thing they remember. This is especially effective in email!

7. Decoy Effect → Use the Rule of Three

Your offer doesn’t live in isolation. It’s being judged against whatever’s beside it. Your brain compares first, decides second. That contrast is what makes one option feel like the right fit. 

The copy strategy to pair this cognitive bias with? The Rule of Three.

Goldilocks wasn’t just about porridge…line up three choices, and one almost always feels like the reasonable one. Try featuring your top three services on your homepage so people can immediately see which one interests them the most. 

8. Ikea Effect → Get Clients Involved

We care more about things we’ve had a hand in building, even if it’s just answering a question or making one small choice instead of putting together a whole bookshelf with some pictures and an Allen key. Once someone’s contributed something, they’re more likely to follow through. It doesn’t feel like your offer—it feels like their thing now.

The copy strategy to pair this cognitive bias with? Client Involvement.

Try creating space in your messaging where people feel like they’ve contributed, not just consumed. An easy way? Turn your contact form into something *lightly* involved that asks questions about your lead’s project goals and hopes. 

9. Loss Aversion → Highlight Fear-Free FOMO

Our brains are wired to avoid loss more than we’re driven to gain. Missing out hurts, and we’ll do a lot to dodge that sting. When people see what they might lose by not acting (progress, peace, time), they’re more likely to move.

The copy strategy to pair this cognitive bias with? Fear-Free FOMO.

Give a gentle nudge toward action by showing what’s at stake, without scaring the sh*t out of your reader. Consider building a before/after section on your sales page that contrasts the stuck-feeling they’re in now with how things could feel on the other side of working with you. 

10. Serial Position Effect → Put Your Best Bits First & Last

We remember the first and last things we see way more than the stuff in the middle. Classic “start strong, end stronger” situation. If you bury the good stuff in paragraph four? It’s gone. People skim, scroll, and peace out, so what they remember most is what you opened with and what you closed on.

The copy strategy to pair this cognitive bias with? Best Bits First & Last.

So what do we do? Start with the part that makes them care, end with the part that makes them act. When writing a blog, lead with something that earns attention and end with something they’ll actually remember (like this one, wrapping things up nice and neat).

Feelings > Logic, And Cognitive Biases Get It

Cognitive biases are just the brain’s way of getting through the day without collapsing under the weight of a thousand micro-decisions. So when you’re writing copy? Building offers? Crafting your next email? Don’t try to outsmart the quirks…use them. 

• Emotion
• Contrast
• Simplicity
• Momentum

Because logic is lovely, but feelings run the show. Always have, always will.

And if this whole “psychology meets marketing” thing is making your copy brain light up like a glow stick?

You need to be on Ask Isobel—my no-BS copy advice column, where I break down stuff like buyer psychology, headline how tos, and uncovering your brand voice.