Ikea made the checkout the farthest point in the store and let exposure do the selling

Researchers estimate that half of all purchases are unplanned, which makes the shopper who deviates from a shopping list the most valuable person in retail. Victor Gruen noticed early that spectacle and display could convert passersby — his Fifth Avenue storefronts reduced the threshold between passerby and product, an effect that now carries his name.

Ikea pushed the idea into floor plan geometry. From the moment you enter, layout designers nudge you onto a specific path through a maze of products, and that path is deliberately the least direct route to the register.

The exposure does the selling: by the time you finally pick up a cart and choose your first item, you have considered the possibility of buying many of the items on display. Researchers have found that increased exposure leads to impulse buys.

A fixed one-way path turns every trip for a £3 pack of plates into a full-catalogue tour.

Impulse purchases grow with exposure, so square footage walked matters as much as shelf space.

The register's distance is the mechanism: the only way out is through more merchandise.

Architecture is a sales tool: decide what customers must see before they can leave, and unplanned purchases follow from exposure, not persuasion.

The forced-path store remains Ikea's signature format worldwide, and retail writers still use the Gruen effect as the standard for what its floor plan achieves — Vox's 2018 explainer treating Ikea as the layout's master practitioner.