ABSTRACT
In order to orient themselves in space while moving from one place to another, mobile organisms take account of the direction and extent of their own movement and the spatial relationships between objects in their environment. In this chapter discussion is limited to the spatial orientation of infants in a stationary environment when the relative position of objects is unchanged but the infants’ views of these objects vary as a consequence of their own self-induced (active) or imposed (passive) movement. The ability to perceive the identity of the spatial location of objects over variations in observer orientation and position has been called position constancy (McKenzie, Day, & Ihsen, 1984). The early development of position constancy—the conditions under which it is manifest and the measurement of its exactness—is reviewed. The question of central interest is when and how infants encode information that allows them to find a fixed target from different viewing points.
