Studies as early as1975 showed that the sets of proteins found in the brains of chimpanzees and humans were virtually identical. The question naturally arose as to why humans and chimpanzees are so different. A new study provides at least a partial answer to the question. Researchers collected brain, liver, and blood samples from humans, chimps, macaques, and orangutans, isolated RNA from each sample and calculated the amount of RNA produced for 12,000 genes. Little difference was found among the species for the liver and blood samples. However, big differences were detected in gene expression between humans and chimpanzees, although gene expression between chimpanzees' and the other primates' brains was about the same. The results show that regulation of gene expression is unique in the human brain compared to all other primates.

Modern humans have brain sizes larger than any other placental mammal relative to body size. The human brain uses a tremendous amount of energy - up to 60% of total energy consumed in newborns. A recent study suggests that the large increase in brain size was balanced by a similar reduction in the size of the gastrointestinal tract. However, other mammals, such as pigs, with small intestines don't have brains as large as ours. In addition, the theory doesn't hold for birds or bats. The presence of large brains in humans presents a problem to evolutionists, since it presents a large energy drain upon the species, especially before the advent of agriculture and reliable food supplies.

The brain is the centre of a complex computer system more wonderful than the greatest one ever built by man. The body’s computer system computes and sends throughout the body billions of bits of information, information that controls every action, right down to the flicker of an eyelid. In most computer systems, the information is carried by wires and electronic parts. In the body, nerves are the wires that carry the information back and forth from the central nervous system. And in just one human brain there is probably more wiring, more electrical circuitry, than in all the computer systems of the world put together.1 Yes, it is a wonderful thing—this brain of ours.

The control centre of the human body is the human brain. It is by far the most complex information-management system in the universe.
In fact, as we look at this very moment, we are actually seeing with our brain. Although, of course, the message is carried there from another marvellous structure, the human eye. Modern cameras operate on the same basic principle as our eyes. In our eye the focus and aperture are adjusted automatically.

’Without a doubt, the most complex information-processing system in existence is the human body. If we take all human information processes together, i.e. conscious ones (language, information-controlled, deliberate voluntary movements) and unconscious ones (information-controlled functions of the organs, hormone system), this involves the processing of 1024 bits daily. This astronomically high figure is higher by a factor of 1,000,000 [i.e., is a million times greater] than the total human knowledge of 1018 bits stored in all the world’s libraries.’