The Decoy Effect — How an Irrelevant Option Changes Your Choice

Context-dependent choice and the asymmetric dominance effect — and how to decide without being manipulated by the comparison set

What is the decoy effect and how does adding a third option change which of two choices people prefer?

The decoy effect, documented by Huber, Payne and Puto (1982), is the finding that adding a third option that is clearly inferior to one of two existing options (but not the other) reliably shifts preference toward the option it is "dominated by." It shows that preferences between options are not fixed: they are constructed in context, and the comparison set shapes the outcome.

In Huber, Payne and Puto’s original study, adding a dominated "decoy" option increased the preference for the option that dominated it — violating the independence-of-irrelevant-alternatives principle that rational choice theory requires. The effect is now one of the most cited findings in behavioral economics and appears in pricing strategies, subscription tiers, political framing, and everyday comparison shopping. Understanding it protects against manipulation and helps you structure choices so others (and you) can evaluate them on their merits.

Practices

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