Consciousness, Sleep, and Altered States


change blindness

failure to notice a change in a stimulus event

circadian rhythms

cyclical biological changes that take place on a roughly 24-hour schedule


subjective awareness of one's internal mental states and external environment


psychoactive drugs that reduce neural activity and slow bodily functions

dissociation theory

theory that hypnosis represents an altered state in which consciousness is split into two components: a hypnotized component (the hypnotized self) and a nonhypnotized component (the hidden observer)

divided attention

attending to multiple sources of information at once

drug tolerance

reduced response to a drug following repeated use

dual-processing theory

theory that divides consciousness into an implicit system and explicit system


psychoactive drugs that distort perceptions and may trigger hallucinations


altered state of consciousness in which a person becomes highly suggestible

inattentional blindness

failure to notice an unexpected object or event when one's attention is focused on something else


disorder in which a person has a hard time falling or staying asleep

lucid dreaming

sleep phenomenon in which dreamers are aware they are dreaming and may be able to exert some control over dreams


chronic neurological disorder that affects the brain's ability to control sleep-wake cycles

night terrors

episodes of screaming, intense fear, and flailing while still asleep

non-REM sleep

sleep stages in which rapid eye movements do not occur


psychoactive drugs that reduce pain

parallel processing

type of information processing in which some or all processes involved in a cognitive task occur simultaneously

psychoactive drugs

drugs that alter consciousness

REM sleep

stage of sleep associated with dreaming, characterized by rapid eye movements

restless legs syndrome

powerful urge to move the legs when lying down, sitting, or falling asleep

selective attention

choosing certain stimuli in the environment to process while ignoring the rest

serial processing

type of information processing in which some or all processes involved in a cognitive task occur one after the other

sleep apnea

sleep disorder in which breathing interruptions occur frequently during sleep

sleep paralysis

inability to move the body just before falling asleep or just after waking up


walking about while still asleep

sociocognitive theory

theory of hypnosis suggesting that hypnosis is a social role in which people hand over responsibility for their actions to the hypnotist and maintain a highly focused state of attention in which they are only dimly aware of what is happening around them


psychoactive drugs that increase neural activity and accelerate bodily functions

withdrawal symptoms

physiologically unpleasant symptoms that occur after a person abruptly reduces or stops long-term use of a drug