IDEA FOUND // IDEA 21

Mind & biases4 MINGuided readContext-dependent

Decoy Effect

A third option appears that nobody wants. Suddenly, one of the first two looks better.

01 / PLAINLY

What it means, plainly

A third option that is worse than one alternative but not the other can make the first look more attractive.

02 / CONTEXT

A little more

An alternative clearly inferior to one option but not another can shift preferences toward the first. The contrast creates an easy local comparison and makes one offer appear dominant.

03 / WHY IT MATTERS

Why it matters

In menus and pricing plans, an unattractive option can change which purchase looks sensible without improving that purchase at all.

04 / EXAMPLE

A familiar example

Between a small coffee at 3 and a large at 5, adding a medium at 4.90 can make the unchanged large look more attractive.

05 / LIMIT

What it does not mean

Decoys do not work identically in every setting, and a third option may provide useful information rather than bias.

06 / NOTICE

Notice it in your day

Take three pricing plans and cover the least appealing one. Check whether your preference between the other two changes, then return to your original criteria.

FINAL NOTE

The idea worth keeping

Compare every alternative with your original criteria, not just with the option placed beside it.

QUESTIONS / 02

Questions people still have

What makes an option a decoy?

It is clearly worse than one alternative on the relevant comparison, but does not play the same role against the other.

Does a third option always create bias?

No. It may add useful information, and any shift in preference depends on the setting.

RESOURCES / 01

Sources you can check

These links show where the explanation comes from. Some are academic and may be more technical.

Editorial review: 2026-08-14

PATHS / 03

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If this idea raised another question, continue along one of these paths.