These 4 Psychology Experiments Changed Marketing Forever
Bonus: Top ideas on how to use them in your next campaign.
📆 Wednesday, 16 Jul 2025
Hey — It's Rhythm. Thrilled to have you back in Ecom Circle, where I spend my time scaling ecom brands & finding best growth strategies to share with you.
DEEP DIVE 💡The biggest breakthroughs in marketing didn’t come from CMO war rooms or flashy Super Bowl ads.
But from quiet psychology labs with clipboards, stopwatches, and very confused college students?
In this edition of EcomCircle, we’re diving into the top psychology experiments that have changed marketing forever—not the obvious stuff you’ve seen on every “Top 10 marketing hacks” list, but the real foundational studies that rewired how we sell, persuade, and build emotional brands.
These aren’t just theories. These are battle-tested ideas that explain why people click, why they buy, and what makes them come back for more.
Each story is packed with real study details, deep commentary, and most importantly—how to apply it right now to your DTC brand.
If you’re a marketing nerd (or want to sound like one on Zoom calls), this one’s for you.
Let’s get into the human brain 🧠
And make it buy.
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1. The Endowment Effect — How “Just Owing” Becomes “Owning” (Kahneman, Knetsch & Thaler, 1990)
🔬 Deep Dive: The Story
It’s 1990, the Cornell campus is buzzing on a typical day—and Richard Thaler, Danny Kahneman, and Jack Knetsch have walked in with a box of coffee mugs stamped with the school logo. They hand these mugs randomly to half of the students in class, letting them inspect their shiny new possessions. The rest watch, coffee-mugless.
Once the mugs are distributed, both groups are asked two questions:
Owners: “What’s the lowest price you’d accept to sell this mug?”
Non-owners: “What’s the highest price you’d pay to buy this mug?”
Conventional economic theory predicts these answers would converge—half the mugs should trade hands at market value. But here’s what happens instead:
The owners won’t sell below $5.25 on average.
The non-owners rarely bid higher than $2.75.
Trades? Only about 5% happen—despite 50% predicted if people were rational.
It’s not just mugs, either. In another round, the donated endowment is chocolate versus mug: same gaps appear. The researchers ruled out income, scarcity, or ignorance—it’s true loss aversion and ownership instinct at work .
🧠 Why It Matters
Ownership—even fleeting—anchors us emotionally. What feels like ours becomes more valuable in our minds. Letting it go feels like a loss, which our brains punish twice as hard as they reward gains.
This psychological quirk is everywhere: from people clinging to losing lottery tickets to users unable to delete “their” free app after uninstalling it.
🛠️ eCom Playbook: Use It Ethically
Cart reminders as “your items”
Instead of “You left items,” try: “Your cart’s waiting for you.” Subtle shift—same effect.
Free sample claim
Allow users to “claim a free sample” (even a digital one). Once claimed, it’s emotionally theirs.
Name-based previews
Display products as “Samantha’s mug” or “John’s sneakers”—the illusion of ownership boosts pull-through rates.
2. The IKEA Effect — We Love What We Build (Norton, Mochon & Ariely, 2011)
🔬 Deep Dive: The Story
Fast forward to 2011. Michael Norton, Daniel Mochon, and Dan Ariely decide to test effort-driven value. They:
Hand participants IKEA boxes to assemble.
Have others fold origami or build with Legos.
Ask a control group to just view the pre-built items.
Next, each group is asked, “What’s the highest price you’d pay for this completed item?”
Here’s where it gets wild:
Self-built items consistently fetched 50–63% higher valuations than pre-made equivalents .
A crucial nuance: only fully completed items triggered the effect. Half-built origami? No bond formed.
The value boost came even when participants admitted their work was imperfect—suggesting the emotional attachment came from agency, not quality.
They liken it to evolution: effort signals ownership and competence (effectance). We see this in nature too—rats and mice, when rewarded harder, prefer those harder-earned rewards .
🧠 Why It Matters
Effort isn’t just weight—it’s glue. When we create, we emotionally invest. Even minor effort builds pride and identification. Suddenly, it’s not just a product—it’s your product.
🛠️ eCom Playbook: Three Ways to Let Customers “Build”
Custom bundle builder
Let users pick a layered kit—breakfast box, workout stack, home office starter—instead of pre-packaged bundles.
Interactive quizzes as creation tools
“Build your wellness routine”: surface 4–5 tailored products. They’re not just recommended—they feel designed by you.
Co-creation launches
Launch 200 customized tote bags based on customer-submitted designs. You build together and they feel ownership in the finished product.
3. The Mere-Exposure Effect — How Familiarity Breeds Affinity (Zajonc, 1968)
🔬 The Story Behind the Study
In 1968, psychologist Robert Zajonc was curious: does repeated exposure alone make us like something more? To test this, he presented participants with a series of stimuli—random shapes, unfamiliar words, even foreign symbols—some repeatedly, others just once.
Then he asked: “Do you prefer one symbol over another?”
Surprisingly, even without understanding or consciously recognizing them, participants consistently rated the familiar stimuli significantly more likable—despite having no logical reason to choose them. Essentially, exposure builds affinity, even when no rational reason is present.
🧠 Why It Works
Familiarity = safety. Our brains are wired to prefer known stimuli because the unfamiliar represents potential risk. Over time, neutral things become comforting simply by being seen. This is why ad frequency matters and why consistent brand visuals build trust.
🛠️ eCom Playbook: Embed Familiarity to Convert
Consistent Ad Sequencing
Serve a series of 3–4 ads introducing one idea/channel before the pitch. By the time it’s the “buy” ad, the brand already feels friendly.
Branded design coherence
Use the same graphic elements across website, email, and social—color palettes, mascots, taglines—so every touchpoint deepens recognition and trust.
Email storytelling pre-wheel pitch
Rather than sending an immediate promotional email, send 2–3 story-based emails leading up to your offer: behind-the-scenes, founder anecdotes, user journeys—so when it’s pitch time, it feels like another chapter, not an intrusion.
4. The Paradox of Choice — Less Is More (Schwartz, 2004)
🔬 The Story Behind the Study
Barry Schwartz’s group tested ice-cream selection in a supermarket display with either 6 or 24 flavors. The booth attracted more browsers with 24 options—but when it came to purchasing, the 6-flavor display won by 500%. Folks loved looking at the variety—but too much choice paralyzes decision-making.
Schwartz dubbed this phenomenon “choice overload,” arguing that too many options increases anxiety, decreases satisfaction, and even prompts regret.
🧠 Why It Works
We believe more choice = more freedom. But our limited cognitive bandwidth means too many options fuel decision fatigue. Feeling overwhelmed squashes action, especially at checkout.
🛠️ eCom Playbook: Simplify to Sell
Curated starters
Offer 3–5 curated kits tailored to common needs—“Routine for Deep Sleep,” “Desk Essentials,” “Snack-Time Favorites”—and label them clearly so shoppers don’t need to search through 20 SKUs.
Guided filters + prompts
Include “Best for…” buttons on product pages. When a user clicks “Best for oily skin,” dynamically show 3 top choices instead of the full board.
Monthly spotlighted picks
Instead of promoting your whole catalog in every email, use a “Top 3” or “Editor’s pick” section. People click more when options are contained, curated, and confidently recommended.
These aren’t academic curiosities—they’re mindsets. Smart marketers use them to create products and flows that feel personal and protective. Clouding it with aggressive tactics hurts trust—but framing it humanely builds connection and loyalty.
If these theories theorems speak to you, let me know, and I’ll unpack other gems in the next edition.