Spatial memory is used to return to rewarding locations (home, foraging sites, and so on) and has been demonstrated in a wide diversity of animals, ranging from the invertebrates through to humans. The particular kinds of information (cues) used are also variable, although visual landmarks, distances, and directions often form the basis for this kind of memory. Almost all tests of spatial memory have been conducted in the laboratory, using mazes of different kinds, relying on food or escape as the motivation for performance. The main brain region involved in processing spatial information (in vertebrates) is the hippocampus, which varies in size in relation to the spatial demands placed on animals by their ecology.