The discovery of the pre-formal and childlike structure of psyche and personality, mind and cognition of „primitive“ man is the most important discovery in the humanities and social sciences. It is the only discovery in the humanities, psychology and social sciences that corresponds to the importance of the evolutionary theory in the biology. This discovery is not only relevant to psychology, sociology, and ethnology; it is relevant to all humanities such as religious studies, Egyptology, sinology, history etc. This discovery is on the list of the big breakthroughs that have been always huge disappointments to the self-esteem of humankind. N. Copernicus overcame the idea that the earth is in the centre of the universe. C. Darwin surpassed the idea that man is directly made by god but is a product of a long evolution from the simplest forms of life. S. Freud showed that the idea of fully reflectivity of man is a mere illusion and J. Piaget contributed to the sciences the fact of the ontogenesis of psyche and rationality. The fact that primitive man has a childlike psyche is the next step on this way of accepting the ideas of evolution and development. The knowledge about the role of developmental psychology to history and social sciences corresponds to the role of Darwinian theory to biology.weiterlesen