COHEN, ROBERT; WEATHERFORD, DAVID L.; LOMENICK, TERRI; and KOELLER, KELLY. Development of Spatial Representations: Role of Task Demands and Familiarity with the Environment. CHILD DEVELOPMENT, 1979, 50, 1257-1260. First and fifth graders estimated all interlocation distances among 6 objects in 1 of 2 environments: a familiar library or a novel arrangement of objects in a room. Estimations were performed in a large empty classroom, with each child receiving 1 of 3 task instructions. The magnitude-estimation task required a rescaling of represented distances, the straight-line-reconstruction task required a reorientation of distance estimates, while the free-reconstruction task required neither a rescaling nor a reorienting of estimates. First graders were as accurate as fifth graders under free-reconstruction instructions but were significantly less accurate in the other instruction conditions. Fifth graders were equally accurate across all three estimation tasks. This pattern of results was the same for judgments of distances in both environments, although both age groups were more accurate for distances in the novel environment than for distances in the familiar setting. These findings support Pick, suggesting an increase in the ability to shift among spatial frames of reference with development, and Piaget and Inhelder's proposed sequence of mastery of spatial knowledge from topological to projective and Euclidean relationships. The roles of task demands and familiarity with an environment for conclusions concerning the nature and development of spatial representations are discussed.