The decoy effect: the useless option that isn't there by accident

At the movie theater: small popcorn $4, large $8. You'd probably take the small. Now watch what one added option does. Small $4, medium $7, large $8. Suddenly the large feels like an obvious deal — only a dollar more than the medium for way more popcorn — and sales of the large jump. The medium isn't there to be bought. It's there to make the large look brilliant. This is the decoy effect (economists call it asymmetric dominance): adding a third, deliberately unattractive option changes which of the original two you prefer, even though nothing about them changed.

How a decoy works

A decoy is an option that is clearly worse than one choice (the 'target' the seller wants you to pick) but not clearly worse than the other. Its job is to be a comparison that makes the target shine. In the popcorn case, the medium is dominated by the large — barely cheaper, much less popcorn — so the large looks like a steal by contrast. Your brain loves an easy comparison, and the decoy hands you one, quietly steering you toward the higher-margin choice while you feel like a savvy bargain-hunter.

Where decoys hide

• Subscription tiers: a 'Basic,' 'Plus,' and 'Premium' where Plus is priced to look bad, pushing you to Premium (or occasionally to make the middle option look like the sweet spot they actually want you in).
• The famous magazine case: web-only $59, print-only $125, print+web $125 — the print-only option exists only to make the combo feel free.
• Product lineups: a barely-cheaper 'lesser' model that makes the flagship feel like obvious value.
• Menus and wine lists: a wildly overpriced item that makes the second-most-expensive one feel reasonable.
• Real estate and car options: a deliberately unappealing listing or trim shown alongside the one they want to move.

Defusing the decoy

1. Decide what you need BEFORE seeing the options. Walk in knowing 'I need the small' or 'I need the basic plan,' and the decoy has nothing to grab.
2. Evaluate each option against your needs, not against each other. The right question is 'does the cheapest one do what I actually need?' — not 'which is the best deal relative to the others?'
3. Distrust the option that feels like an obvious steal. When one choice suddenly looks brilliant because of a nearby option, ask whether that neighbor exists to make it look brilliant.
4. Ignore the tier nobody would rationally pick. A clearly-dominated option is usually a decoy; its presence is information about the seller's intent, not about value.
5. Restate prices in absolute dollars per year. '$22 vs $20' feels like nothing; '$264/year vs $240/year for features I won't use' breaks the spell.

The bottom line

The decoy effect proves your preferences aren't fixed — they can be steered by adding an option you'd never choose, positioned to make a pricier one glow. Sellers arrange menus, tiers, and lineups around this on purpose, and it works even when you know the trick. Your defense is to decide what you need before you look, judge each option against that need rather than against its neighbors, and cover the suspiciously-perfect deal to see if it survives. The option that only looks good next to a worse one was never the good option. It was the target.