Cognitive Bias
Mental shortcuts help us judge quickly, but they can also produce predictable mistakes.
People do not enter a decision as neutral calculators.
Show one price before another and the first number becomes a reference point. Make one option the default and it gains momentum before anyone compares it. These effects are easy to use and just as easy to abuse.
Origin
Tversky and Kahneman's 1974 paper described representativeness, availability, and anchoring. They found that these useful shortcuts can also produce systematic errors in judgment under uncertainty.
Audit the first number, option, and example people see. Early information can shape every comparison that follows.
Treat defaults as design decisions with consequences. Use them to reduce routine effort, not to steer people toward an outcome they would reject.
Show relevant context beside a claim. Base rates, ranges, and plain-language explanations can counter a vivid but misleading example.
Invite a second view during design reviews. Ask what evidence is missing, who benefits from the framing, and what could change the conclusion.
Digital systems
A default privacy setting
A preselected option is easier to accept than to reconsider. The interface should explain the consequence clearly and make a more private choice just as easy to select.
Physical signals
The first price on a menu
An unusually high first price can change how the prices below it feel. The number becomes an anchor even when it is not the option most people intend to choose.
Order, wording, defaults, or visual emphasis push judgment in one direction without making that influence visible.
Make the framing explicit, provide the context needed to compare, and remove manipulative defaults or urgency that works against the person's interests.