Changes in the developmen of the primate brain during the evolution cannot be shown only in regards to the aspect of brain size and its differentiation, rather it has been shown that primate brains have changed in very specific ways at certain points in history. To understand how certain changes in the brain and nervous system of primates are reflected in their behavior, lifestyle and cognition, comparative studies should be conducted on a wide range of mammals, especially strepsirchines and anthropoid primates, and with animals thought to be closely related to primates to get a better picture from an evolutionarly point of view. It is currently not possible to draw strong conclusions as to why some parts of the nervous system has evolved and acquired the properties that it has. An example would be the blobs with rich CO in area V1. We need methods to develop better theories of structure to function relationship because current theorise do not give us enough insight in a detailed enough manner. With the increasing development of molecular biology, bioinformatics and molecular genetics, we can expect to gain increasing insight into the evolution of the primate brain at the molecular level that we will then be able to link to a change in phenotype.