A paradigmatic model of cultural ideology provides a context for understanding the relationship between decision-making and personal and cultural rationality. Cultural rules or heuristics exist which indicate that many decisions can be made on the basis of established strategy rather than continual analytical calculations. When an optimal solution to a problem does not exist, decisions may be aimed at a range of acceptable outcomes determined on the basis of past experiences, the achievements of others, and the degree to which one perceives himself as being in control of events. According to this theory, culture is an information system and a general heuristic model that individuals use as an intermediating device for interpreting, understanding, and interacting with the social and physical environments. Culture provides information and then organizes that information as individuals synthesize facts, experience, and inherited traditions into a world view. This model provides for creativity as a factor as individuals interpret their world view or cultural ideology and in so doing, helps explain the cultural variation necessary for evolution. Adjustments in systems of information, world view, and theory become necessary because, in the process of integrating new information or expectations, the current system is subject to increasing internal stress. Cultural change serves as an adjustment to the accumulation of information or experience which the current cultural system does not adequately account for. (LP)