Geometry and Force Dynamics in Simple Spatial Terms: Two Theories, One Resolution

Basic spatial terms such as the English prepositions “in,” “on,” “above,” “below,” “left,” and “right” represent spatial relationships that are encoded in languages of the world and are readily learned by young children. How do children learn these terms, and what are the relative contributions of universal foundations from spatial cognition versus language-specific input? I argue that progress can be made on this issue by recognizing two distinct subclasses of spatial terms, each rooted in different classes of spatial properties, leading to different kinds of learning problems for the child. “Geometric” terms such as “above,” “below,” “left,” “right,” and “behind” focus on spatial properties such as the distance and direction between two objects, specified by orthogonal axes centered on a reference object and vectors that define the location of one object relative to the other. By contrast, “force-dynamic” terms such as “in” and “on” focus on the physical and mechanical properties of objects that specify how one object interacts with the force-dynamic properties of the other. The two sets of terms show different degrees of cross-linguistic variation and present different problems for learners, leading to different developmental trajectories and mechanisms of acquisition. They may ultimately derive from fundamentally different cognitive domains—space and objects.