We show that the dynamics between inherent structures in glassforming systems can be understood in purely dynamical terms, without any reference to "topographic" features of the potential energy landscape. This "nontopographic" interpretation is based instead on the existence of dynamical heterogeneities and on their statistical properties. Our view is supported by the study of simple dynamically facilitated models of glassformers. These models also allow for the formulation of quantitative theoretical predictions which are successfully compared to published data obtained in numerical and experimental studies of local dynamics of supercooled liquids. (C) 2003 American Institute of Physics.