The Puzzle of Consciousness

1		is defined as our moment-to-moment awareness of ourselves and our environment. It is subjective, private, dynamic, and central to our sense of self. One of the earliest theorists about consciousness was , who believed that the mind contains three levels of awareness, the conscious mind, the preconscious mind, and the unconscious. Today, cognitive psychologists believe that both conscious and unconscious thought are complementary forms of information processing. People use both voluntary attention and conscious effort, or processing, and processing, which is performed with little or no conscious effort. Automatic processing facilitates , which allows us to do more than one thing simultaneously.

Circadian Rhythms: Our Daily Biological Clocks

2		The daily biological cycles that we are all subject to are called rhythms. These daily cycles are regulated by the of the hypothalamus. Environmental disruptions such as jet lag, night-shift work, and changes of season can affect circadian rhythms. A disorder called is a cyclic tendency to become psychologically depressed during certain months, which may result from a circadian rhythm disruption.

Sleep and Dreaming

3		When we are awake and alert, our brains show an EEG pattern of waves, while waves typically occur when we are relaxed or drowsy. Approximately every 90 minutes of sleep, we cycle through different stages of sleep. Stage 1 is a stage of light sleep, while Stage 2 is characterized by in the EEG pattern. Stages 3 and 4 are characterized by waves in the EEG pattern, and, together, they are called - sleep. Rapid eye movements and relaxation of the muscles due to lost muscle tone occur during sleep. It is not exactly clear why we sleep. The model argues that we sleep in order to recover from physical and mental fatigue. / models argue that the main purpose of sleep is to increase a species’ chances of survival. Many people suffer from sleep disorders. A chronic difficulty in falling asleep is called . Extreme daytime sleepiness and sudden, uncontrollable sleep attacks are characteristic of . When the loss of muscle tone that causes normal REM sleep "paralysis" fails to occur, a person experiences - . People who repeatedly stop and restart breathing during sleep suffer from . Dreams more intense than nightmares often suffered by children are called . Freud believed that main function of dreaming is , and distinguished between a dream’s manifest content (the surface story) and the content, the disguised psychological meaning of the dream. A more modern theory argues that dreams are the result of the action of the cortex as it tries to make sense of random nerve impulses. This theory is called - theory. According to - models, dreams can help us find creative solutions to problems. Theories that focus on the role dreams may have in storing day to in information are called - theories. Sometimes people daydream a lot and live in a vivid fantasy world that they control. Such people are said to have a - personality.

Drugs and Altered Consciousness

4		A special lining of tightly packed cells that screens out many foreign substances but lets vital nutrients and many drugs through is called the - . When a drug is used repeatedly the intensity of effects the drug produces tends to decrease over time, a process called . Because drugs affect homeostasis, the brain tries to adjust for the imbalance by producing responses. The occurrence of compensatory responses after discontinued drug use is called . Drugs that decrease nervous system activity are called , while drugs that increase neural firing are called . Excessive use of alcohol, a depressant, may result in a "shortsightedness" in thinking that may cause people not to monitor their own actions or think about the long-term consequences of their behavior, a phenomenon called . Powerful mind-altering drugs that produce hallucinations are called .

Hypnosis

5		Hypnosis is a state of heightened suggestibility in which some people are able to experience test suggestions as if they were real. A standard series of pass/fail questions to determine the degree to which a person is subject to hypnotic induction is called a . theory proposes that hypnosis involves a division of awareness such that a person simultaneously experiences two streams of consciousness. A second set of theories of hypnosis called - theories suggest that people under hypnosis are simply acting out social roles.