Definition
Decoy Effect (also called attraction effect): When a third option that is clearly inferior to one of the original two on most dimensions is added, people become more likely to choose the option that the decoy makes look better; without the decoy, preferences between the two original options may be more balanced.[1]
Theoretical background
Huber, Payne & Puto (1982) systematically demonstrated in consumer choice experiments how an asymmetrically dominated option shifts preferences.[1] The effect violates independence of irrelevant alternatives in classical rational choice.
Typical scenario
Example: Plan A $50 / standard specs, Plan B $80 / large specs. If you add C: $85 / specs slightly worse than B, then B looks “better value–and more people choose B; C is the decoy.
In consumer decisions
| Scenario | How it is used |
|---|---|
| Bundle pricing | Place a slightly pricier but worse option next to the mid-tier to highlight it |
| Subscription tiers | Middle tier is contrasted with a high-price, low-value tier |
| Three-way product choice | Third option is designed purely to make the featured option look better |
Place in Selection Logic
The decoy effect is a form of situational manipulation of preferences. Spotting the decoy and comparing only on dimensions you care about via fit score helps maintain selection immunity, in line with T5 Immunity Theorem.
Mitigation
- Ignore clearly dominated options: If one option is worse than another on all key dimensions, drop it from the comparison.
- Compare only on dimensions you care about: Use multi-dimensional evaluation to set your weights and avoid being pulled by the decoy.
- Two-option framing: Ask “If only A and B existed, which would I choose?” before considering a third.