The Decoy

Sometimes. Adding an option that one choice beats on every count can raise that choice's share, but mainly when options are described in numbers. In 91 attempts to produce the effect, only 11 found it reliably. At an online diamond retailer, decoys were rarely noticed but lifted profit by about 14 per cent.

What the report found

1. The original finding broke a basic rule of rational choice. Adding an option should never raise the share of an option already on offer. In 1982, adding a dominated decoy did exactly that, across many product categories.
2. The famous examples are striking. In a widely told classroom test, adding a print-only magazine subscription that nobody chose raised the share choosing the print and web bundle at the same price from 32 to 84 per cent.
3. The effect reaches beyond shopping. Honeybees and gray jays showed similar shifts in choice, and the effect appeared in simple perceptual judgements.
4. It is less robust than its reputation. In 91 attempts to produce the effect, only 11 found it reliably. It largely disappeared when options were shown with pictures or real experience rather than numbers.
5. In a real market, it worked when noticed. At an online diamond retailer, shoppers detected decoys only 11 to 25 per cent of the time, but when they did, the better diamond sold much faster, and the effect raised gross profit by about 14 per cent.

What is inside

1. The idea and where it came from
2. The original studies, explained
3. What happened when others tested it
4. Where researchers disagree
5. What we can say with confidence

Plus a timeline of the research, a diagram of how a decoy works, a summary-of-findings table and a graded list of claims.

Who it is for

For anyone who designs price lists, plans or menus, and anyone who has wondered why the middle option looks so good.

How we work

Evidence Reviews take one well known idea and ask what the research actually shows, from the original studies to the replications. Every claim is graded Established, Emerging or Untested. Where researchers disagree, as they do on how robust the decoy effect is, both sides are set out before we say where we stand.

Cite this report

The Why We Project (2026) The Decoy: The third option nobody buys. Evidence Review No. 05. Dubai: Why We Tech Ltd. Available at: thewhyweproject.com