Distributed schemes associate a set of units and their activation states with particular symbols or values. For example, Feldman (2006) proposes that concepts are represented by the activity of a cluster of neurons; triples of such clusters representing a concept, a role, and a filler (value) are linked together by triangle nodes to represent simple attributes of objects. Language understanding is treated as a kind of simulation that maps language onto a more concrete domain of physical action or experience, guided by background knowledge in the form of a temporal Bayesian network.