The context in which a choice is presented changes what we pick.
The order of a menu, the options already preselected on a form, or which alternative appears first on a list: all of that is choice architecture, the deliberate design of the context in which people choose.
Every decision happens within a context that someone, intentionally or not, already designed. That context (which options exist, in what order, which one comes as the default, how each is described) shapes the outcome as much as the actual content of the options. Choice architecture is the discipline of designing that context deliberately.
There's no "neutral" way to present a choice. Any form, menu, or screen already has an order, a font size, and a default option, whether or not those were chosen on purpose. The real question is whether you're going to design that context with intention or leave it to chance.
People don't evaluate each option in isolation and with perfect rationality. The order, format, and default of a choice act as shortcuts that shape the final decision, even when the content of the alternatives hasn't changed.
Source: Thaler, R. H. & Sunstein, C. R. (2008). Nudge: Improving Decisions About Health, Wealth, and Happiness, where the term was coined.
Designing the choice architecture of a sign-up form, a checkout, or a digital government process (what goes first, what's marked by default, how many steps it has) usually has more impact on the outcome than redesigning the content or the offer itself.
Related concepts
