Cranial capacity
The size of the brain is a frequent topic of study within the fields of anatomy and evolution. Brain size is sometimes measured by weight and sometimes by volume (via MRI scans or by skull volume). Neuroimaging intelligence testing can be used to study brain size of different sexes. One question that has been frequently investigated is the relation of brain size to intelligence.
The balance of findings for human brain size, largely based on participants of European ancestry, indicates an average adult brain volume of 1260 cubic centimeters (cm3) for men and 1130 cm3 for women. There is, however, substantial variation; a study of 46 adults aged 22–49 years and of mainly European descent found an average brain volume of 1273.6 cm3 for men, ranging from 1052.9 to 1498.5 cm3, and 1131.1 cm3 for women, ranging from 974.9 to 1398.1 cm3.
The right cerebral hemisphere is typically larger than the left, whereas the cerebellar hemispheres are typically closer in size. The adult human brain weighs on average about 1.5 kg (3.3 lb). In men the average weight is about 1370 g and in women about 1200 g. The volume is around 1260 cm3 in men and 1130 cm3 in women, although there is substantial individual variation.
From early primates to hominids and finally to Homo sapiens, the human brain has continued to grow. The volume of the human brain has increased as humans have evolved (see Homininae), starting from about 600 cm3 in Homo habilis up to 1600 cm3 in Homo neanderthalensis, which was the hominid with the biggest brain size. The increase in brain size stopped with neanderthals. Since then, the average brain size has been shrinking over the past 28,000 years. The cranial capacity has decreased from around 1,550 cm3 to around 1,440 cm3 in males while the female cranial capacity has shrunk from around 1,500 cm3 to around 1,240 cm3. Other sources with bigger sample sizes of modern Homo sapiens find approximately the same cranial capacity for males but a higher cranial capacity of around 1330 cm3 in females.
...
Wikipedia