Spatial memory and orientation – knowing what is where and how to get there – are vitally important for our daily life. Without it we would continuously be searching for our keys and glasses, and we would not be able to find our way back home or navigate through our surroundings. It has been estimated that spatial memory and orientation are among the prime functions affected by normal and pathological aging such as in the case of Alzheimer disease. Partly, this is not surprising because these functions are relatively complex, requiring planning, mental manipulation and synthesis, and decision making. Interestingly, the ability to construct spatial representations of the outside world and to store them in memory has been argued to have formed the driving force behind the evolution of all higher cognitive functions in men. While several species of birds, mammals and nonhuman primates appear to posses clear spatial abilities, these never reach the variety and complexity of the human system. This STREP proposal aims for an ambitious, exhaustive examination of the cognitive organization of spatial 46 memory and orientation; of how this important ability is implemented in the human brain and how this contrasts to similar abilities in other species; of delineating which spatial functions are uniquely human and why they are so. These higher order spatial functions include perspective taking, verbally communicating spatial information, and planning one’s way through complex environments. Today’s modern society places enormous loads upon our ability to navigate through the world. Understanding how the human navigational and updating system works has direct practical, social gains. We specifically will try to map the individual differences in spatial ability (e.g. gender, age and cultural) and the needs and preferences different individuals have in dealing with the spatial structure of their environments (women/ men, blind, elderly and brain damaged individuals).