body when it was itself not physical. He said there was a dualism between the realm of thought and the realm of the body and believed that the brain played a role. Sigmund Freud addressed consciousness. He said there were three levels of awareness. These are the conscious, the preconscious, and the unconscious. They relate to his ideas of the id, the ego, and the superego. The conscious is the alert state, with awareness of the internal and external environment. The preconscious are where memories are stored and retrieved. The unconscious are things outside the awareness that cannot be retrieved or are felt to be unacceptable. They still have the capacity to influence behavior. Modern theorists have studied consciousness. There is a theory that consciousness is related to a person s developmental level. Social psychologists see consciousness as related to cultural influences with language playing a big role in the experience of reality. Neurobiologists see consciousness as purely a function of the biology of the brain.
SLEEP AND STAGES OF SLEEP People spend a third of their lives just sleeping. Sleep varies greatly in the animal kingdom, with little sleep gotten by amphibians and dolphins and certain death to rats who die from sleep deprivation. Sleep involves decreased physical activity and reduced awareness. Sleep rebound happens when people fall asleep faster after a period of deprivation. There are multiple brain areas that work together to facilitate and regulate sleep. These include the pons, the hypothalamus, and the thalamus. The thalamus and the hypothalamus together help control slow-wave sleep, while the pons participates in REM or rapid eye movement sleep. There are hormones associated with sleep. These include melatonin, growth hormone, luteinizing hormone (LH), and follicle stimulating hormone (FSH). It is during sleep that FSH and LH are secreted so sleep seems to be important in the generation of normal sexual function. Growth hormone is released by the pituitary gland in response to sleep. 82