Tsotsos 1984 : A cooperative processing scheme is presented that deals with time-varying information. Moreover, it operates over a knowledge base of temporal concepts, organized along common representational axes: generalization, aggregation, similarity and temporal precedence. A hypothesize and test reasoning framework is used to activate hypotheses from this knowledge base, and the active hypothesis structure changes with time. Several interacting search mechanisms, driven by the knowledge organization axes are responsible for activation of relevant hypotheses. Through the temporal cooperative process, hypothesis ranking, instantiation and deletion is achieved. This process treats static and dynamic data in the same way - as samples over time, and thus, sampling issues are directly addressed. The key elements of the computation involve only the hypothesis-data matching success and the conceptual neighborhood of the hypothesis. This mechanism has been implemented within an expert systems framework for motion understanding, with a particular incarnation being the ALVEN system for the interpretation of the dynamics of the human left ventricle from X-ray films.