The brain of a chimpanzee has a volume of 370mL on average. In contrast, humans have a brain size of 1350mL on average. Brain size alone, however, is not an absolute indicator of intelligence. . The structure and organization of the various parts of the brain is a better way of determining intelligence. Human brains have a high surface area because they are much more wrinkled than chimpanzee brains, with greater numbers of connections between many of its parts. These, as well as a relatively larger frontal lobe, allow us much more of the luxury of abstract and logical thought.