consciousness

our awareness of ourselves and our environment

cognitive neuroscience

the interdisciplinary study of brain activity linked with cognition

dual processing

the principle that information is often simultaneously processed on separate conscious and unconscious tracks

visual perception track

to recognize things and to plan future actions

visual action track

guides our moment-to-moment actions

cocktail party effect

ability to attend to only one voice among many

selective attention

the focusing of conscious awareness on a particular stimulus

change deafness

failing to notice changes in voices

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

change blindness

failing to notice changes in the environment

choice blindness

failure to see a change made in one's choice

pop-out phenomenon

strong, distinct stimuli that catches our attention and demands to it

circadian rhythm

the biological clock; regular bodily rhythms that occur on a 24-hour cycle

REM sleep

rapid eye movement sleep, recurring sleep stage during which vivid dreams commonly occur

suprachaismatic nucleus

a pair of grain-of-rice-sized, 20,000-cell clusters in the hypothalamus; does its job by causing the brain's pineal gland to decrease the levels of melatonin in the morning or increase it in the evening

melatonin

sleep-inducing hormone

alpha waves

the relatively slow brain waves of a relaxed, awake state

sleep

periodic, natural, reversible loss of consciousness

hallucinations

false sensory experiences, such as seeing something in the absence of an external visual stimulus

delta waves

the large, slow brain waves associated with deep sleep

hypnagogic sensation

stage 1 of sleep, point between wakefulness and sleep; fantastic and vivid images felt

sleep spindles

bursts of rapid, rhythmic brain-wave activity

sleeeptalking

can occur during stage 2 or any other sleep stage; usually garbled or nonsensical

sleepwalking

end of deep sleep of stage 4; acting out one's dreams by rising out of bed

insomnia

recurring problems in falling or staying asleep

narcolepsy

a sleep disorder characterized by uncontrollable sleep attacks

sleep apnea

a sleep disorder characterized by temporary cessations of breathing during sleep and repeated momentary awakenings

night terrors

a sleep disorder characterized by high arousal and an appearance of being terrified

dream

a sequence of images, emotions, and thoughts passing through a sleeping person's mind

manifest content

according to Freud, the remembered story line of a dream

latent content

according to Freud, the underlying meaning of a dream

REM rebound

the tendency for REM sleep to increase following REM sleep deprivation

hypnosis

a social interaction in which one person suggests to another that certain perceptions, feelings, thoughts, or behaviors will spontaneously occur

posthypnotic suggestion

a suggestion, made during a hypnosis session, to be carried out after the subject is no longer hypnotized

dissociation

a split in consciousness, which allows some thoughts and behaviors to occur simultaneously

psychoactive drug

a chemical substance that alters perceptions and moods

tolerance

the diminishing effect with regular use of the same dose of a drug, requiring the user to take larger and larger doses before experiencing the drug's effect

withdrawal

the discomfort and distress that follow discontinuing the use of an addictive drug

physical dependence

a physiological need for a drug, marked by unpleasant withdrawal symptoms when the drug is discontinued

psychological dependence

a psychological need to use a drug, such as to relieve negative emotions

addiction

a compulsive drug craving and use, despite adverse consequences

depressants

drugs that reduce neural activity and slow body functions

barbiturates

(AKA tranquilizers) drugs that depress the central nervous system and its activity, reducing anxiety but impairing memory

opiates

opium and its derivatives, they depress neural activity, temporarily lessening pain and anxiety

stimulants

drugs that excite neural activity and speed up body functions

amphetamines

drugs that stimulate neural activity, causing speeded-up body functions and associated energy and mood changes

meth

a powerfully addictive drug that stimulates the CNS, with speeded-up body functions and associated energy and mood changes; over time, appears to reduce baseline dopamine levels

Ecstasy (MDMA)

a synthetic stimulant and mild hallucinogen; produces euphoria and social intimacy

hallucinogens

psychedelic drugs, such as LSD, that distort perceptions and evoke sensory images in the absence of sensory input

LSD

a powerful hallucinogenic drug; also known as acid

THC

a major active ingredient in marijuana; triggers a variety of effects, including mild hallucinogens

near-death experience

an altered state of consciousness reported after a close brush with death