 For instance, suppose the structures to be grasped are represented by “causal maps” or “dependence maps”—maps with nodes representing variables that can take on different values and thus represent directions of dependence (Gopnik &amp; Glymour 2002; Gopnik et al. 2004). In the schematic image below, from Gopnik et al. (2004), the map represents a system in which changes to the value of Z bring about changes to the value of S, changes to the value of S bring about changes to the values of X and R, and so on.