Brain Growth Suppresses Body Growth in Children

The metabolic costs of brain development are thought to explain the evolution of humans’ exceptionally slow and protracted childhood growth; however, the costs of the human brain during development are unknown. We used existing PET and MRI data to calculate brain glucose use from birth to adulthood. We find that the brain’s metabolic requirements peak in childhood, when it uses glucose at a rate equivalent to 66% of the body’s resting metabolism and 43% of the body’s daily energy requirement,...

 Effect of Human Brain Size on Labor and Bipedalism

The real obstetrical dilemma came long after Lucy and her colleagues became extinct, when there was a sudden upsurge in brain expansion. About 1.5 million years ago, die adult hominid brain went from the Australopithecine size of 400 cubic centimeters to 750 cubic centimeters in a species called Homo habilis, the first member of our genus. In other words, the brain just about doubled in size. A mere million years later. the hominid brain doubled once again until it reached its present average...

 Breast Feeding Fuels Big Brains

The study looked at the average pregnancy term, breast-feeding length and brain size of 128 species of mammals. They saw that between different species brain size at birth was determined by the length of pregnancy, while the brain growth after birth was determined by breast-feeding duration. [...] The extreme length of pregnancy and breast-feeding in humans (nine months and three years, respectively) is required for the growth and development of our large brains, which can reach 79 cubic in...