Guttman scale analysis is a very useful tool to understand the evolution of societies. It shows the accumulation of cultural traits throughout history in various societies and that those cultural traits were usually accumulated in the same order. The results of studies, by Robert Carneiro and others, shows the accumulation of cultural traits is not random and indicates a universal pattern in cultural evolution. The universal pattern is caused by increasing human knowledge of the environment we live in. Human societies usually acquire this knowledge in the same order, with easier discoveries concerning the natural world being made earlier than more complex discoveries. This means human social and cultural history, usually follows a particular course, a course that is determined by the structure of the human environment.