In spoken languages, children acquire locative terms in a cross-linguistically stable order. Terms similar in meaning to in and on emerge earlier than those similar to "front" and "behind," followed by "left" and "right." This order has been attributed to the complexity of the relations expressed by…

Theories of cognitive development must address both the issue of how children bring their knowledge to bear on behavior in-the-moment, and how knowledge changes over time. We argue that seeking answers to these questions requires an appreciation of the dynamic nature of the developing system in its full, reciprocal complexity. We illustrate this…