Reconstruction of the past based on the production of computerized models. The computer model describes ancient conditions and variables and those are used to generate a sequence of events that are compared against the known archaeological record. The computer imitates the dynamic behavior of an explicit model and helps scientists examine how such systems respond to changing conditions and also to refine and test hypotheses about the past. In an example study of hunter-gatherers, the effect of various changes in the natural environment on such factors as the population settlement pattern or subsistence could be monitored; or the growth of a settlement system could be studied under different conditions of population, economy, technological, or environmental change. The relationships between the various elements in the cultural system must be specified, and then any variety of actual conditions can be simulated. The data used could be derived from observations and the simulation used to examine the effect of different assumptions; the results could then be compared to the observed data to test their validity.