The Human Brain

Cerebrum

Corpus Callosum Cerebrum Pituitary Hypothalamus

“In the most intelligent races, as among the Parisians, there are a large number of women whose brains are closer in size to those of gorillas than to the most developed male brains. This inferiority is so obvious that no one can contest it for a moment; only its degree is worth discussion.

All psychologists who have studied the intelligence of women, as well as poets and novelists, recognize today that they represent the most inferior forms of human evolution and that they are closer to children and savages than to an adult, civilized man. They excel in fickleness, inconstancy, absence of thought and logic, and incapacity to reason.

Without doubt there exist some distinguished women, very superior to the average man, but they are as exceptional as the birth of any monstrosity, as, for example, of a gorilla with two heads; consequently, we may neglect them entirely.” – Gustave LeBon, 1879 Founder of Social Psychology

Morton’s final summary of craqnial capacity by race German, English, Am92 sq in Semitic89 Mongolian group82 Malay group85 Peruvian, Mexico79 Barbarous tribes84 Negro group83 Australian aborigian75

Bean’s Plot Width of brain Length of brain White black

Gould used more modern methods Blind test Adjust for body size Adjusted for cause of death Adjusted for age at death

Mall’s Plot – Steven Jay Gould Width of Brain Length of Brain

Neurotransmitter Synapse

The human brain – Flexible ciruitry 50 billion neurons (chimps have 5.5 billion) Each of these neurons can receive messages from 1,000 other neurons An also send messages to 1,000 other neurons

Brain development after birth Before birth and for 6 months after birth 500,000 new neurons are produced each minute. Brain doubles in size from birth to 1 year Doubles again by age 4 – reaching adult size by 4 or 5.

Ruth Bleier’s Theory of Intelligence Intelligence is a complex entity of: brainbehavior mind bodyenvironment The parts of this complex are inextricable from one another. The parts and the whole are ceaselessly interacting and changing and carry within themselves the entire history of their interactions.

Back to flexibility of circuitry The functional validity of developing synapses occurs through environmental input as a means by which neurons acquire normal anatomical connections and function. Different experiences will develop different anatomic connections.

Ruth Bleier -Genes cannot encode for all the complex behavior for a species that occupies every possible niche -We learn how we are supposed to be -Culture – values, beliefs, expectations, conformity become known as: HUMAN NATURE