Built from published audits

Cognitive biases, with the brands actually using them

Most pages about cognitive bias give you a definition and a lab experiment from 1974. This one gives you 329 examples from 24 biases, each one a real company, each linking to the full teardown of what they did and why it worked.

Written by an Industrial and Organizational Psychologist who audits brands for a living, which is a different job from summarising a textbook.

329brand examples, each linked to its audit
24biases with at least one example
47brand psychology audits read
The index

Biases, most examples first

All audits →

Scarcity

32 brands doing this:

Something becomes more wanted the moment it looks like it might run out, whether or not it was wanted before.

Social proof

28 brands doing this:

When people are unsure what to do, they copy what other people are already doing, and the less certain they are the harder they copy.

Loss aversion

26 brands doing this:

Losing something hurts roughly twice as much as gaining the same thing pleases, so "do not lose this" moves people harder than "gain this".

Framing

26 brands doing this:

The same fact persuades differently depending on how it is worded. Ninety percent fat free and ten percent fat are the same yoghurt.

Anchoring

24 brands doing this:

The first number someone sees sets the scale for every number after it, including numbers that have nothing to do with the first.

Endowment effect

22 brands doing this:

Once something feels like yours, you price it higher than you would ever have paid for it. Free trials work on this.

Reciprocity

17 brands doing this:

Give someone something first and they feel owed, even when the thing given cost almost nothing.

Sunk cost

16 brands doing this:

People keep going because of what they have already spent rather than what they will get, and the more they have spent the harder it is to stop.

Choice overload

16 brands doing this:

Past a handful of options, adding more makes choosing harder rather than better, and the common result is choosing nothing.

Mere exposure

13 brands doing this:

Seeing something repeatedly is by itself enough to start liking it. No argument is required and none is remembered.

Halo effect

13 brands doing this:

One thing people like about something spreads to everything else about it, including things they have not looked at.

Nostalgia

12 brands doing this:

A memory of who you used to be attaches itself to what is being sold, and the feeling gets credited to the product.

Peak-end rule

12 brands doing this:

People judge an experience by its most intense moment and its last moment, not by its average or its length.

Fear of missing out

10 brands doing this:

Acting to avoid being left out rather than because the thing itself was wanted.

Authority

9 brands doing this:

A badge, a title or a white coat makes a claim feel already checked, so nobody checks it.

Decoy effect

8 brands doing this:

A third, deliberately worse option exists to make one of the other two look obvious. It is not there to be bought.

Bandwagon effect

8 brands doing this:

Commitment and consistency

7 brands doing this:

Default effect

7 brands doing this:

Reactance

7 brands doing this:

Push someone toward a choice too hard and they push back, choosing against it to prove the choice was theirs.

Priming

6 brands doing this:

Zeigarnik effect

5 brands doing this:

This index stays free

How each of these is built, and how it breaks

This page shows you which companies use which bias. The question it leaves open is the practical one: how do you build one, what makes it stop working, and where is the line past which it stops being persuasion?

The Cognitive Bias Playbook for Marketers answers that for all twenty-four, and opens with the three that are over-claimed everywhere — including colour psychology and the paradox of choice — and what actually survives scrutiny.

The Cognitive Bias Playbook — $39 All 31 teardowns, collected — $79

Every audit linked from this index is free to read in full on this site, and stays that way.