Attention, memory and perception
Method of loci
Also called Memory palace
People remember things better when they link them to places, which is why a stable layout helps people find their way around a product.
The memory technique places each item in a familiar room or route, then walks through it to recall them. Spatial memory is strong and lasting.
Interfaces benefit from the same thing: when navigation, panels and tools stay in the same place, people remember where things are. Moving them around breaks that memory.
In practice
A design tool that keeps its layers on the left and properties on the right in every mode lets people reach for them without looking.
Common mistake
Reordering menus by how often items are used. It seems helpful, but people lose the places they'd learned.
Where it comes from
An ancient technique credited to the Greek poet Simonides of Ceos and described by Cicero in De Oratore (55 BC).