Why does walking down more store aisles lead to more unplanned purchases even when a shopper carries a list?

Answer: More aisles keep showing products and displays that remind shoppers of things to buy.

A list blocks out product cues, so walking more aisles cannot change what shoppers buy. — A list does narrow the goal and can cut some unplanned buys, but it does not erase what the store shows. Products can remind shoppers of forgotten needs or spark new wants even when the list is in hand. A list filters goals; it does not block product cues, so exposure to aisles still matters.

Checkout candy is the only temptation, so extra aisles give shoppers nothing more to notice. — Checkout candy is a real impulse zone, but it is not the only one. Stores also put tempting products and displays along the aisles, so a longer walk adds more chances to notice something. If only the register mattered, limiting aisles and time would not reduce unplanned buying.

More aisles keep showing products and displays that remind shoppers of things to buy. ✓ — Right: A list keeps a shopper's goals in mind, but every extra aisle adds shelves, displays, and product reminders. Those cues can revive a forgotten need or create a new want, so unplanned purchases become more likely. In-store decision research found that list use, fewer aisles, and less time reduced unplanned buying, while visiting more aisles and browsing more items went with more of it.