unit 1 v2

consciousness

Our subjective awareness of ourselves and our environment.

cognitive neuroscience

The interdisciplinary study of the brain activity linked with cognition (thinking, knowing, remembering, and communicating).

dual processing

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

blindsight

A condition in which a person can respond to a visual stimulus without consciously experiencing it.

parallel processing

Processing multiple aspects of a stimulus or problem simultaneously.

sequential processing

Processing one aspect of a stimulus or problem at a time; used to process new information or to solve difficult problems.

sleep

A periodic, natural loss of consciousness — as distinct from unconsciousness resulting from a coma, general anesthesia, or hibernation.

circadian rhythm

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

REM sleep

Rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur.

alpha waves

The relatively slow brain waves of a relaxed, awake state.

NREM sleep

Non-rapid eye movement sleep; encompasses all sleep stages except for REM sleep.

hallucinations

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

hypnagogic sensations

Bizarre experiences while transitioning to sleep, such as jerking or a feeling of falling.

delta waves

The large, slow brain waves associated with deep sleep.

suprachiasmatic nucleus (SCN)

A pair of cell clusters in the hypothalamus that controls circadian rhythm.

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.

REM sleep behavior disorder

A sleep disorder in which normal REM paralysis does not occur; may involve twitching or acting out dreams.

dream

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

REM rebound

The tendency for REM sleep to increase following REM sleep deprivation.

sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies.

sensory receptors

Sensory nerve endings that respond to stimuli.

perception

The process by which our brain organizes and interprets sensory information.

bottom-up processing

Information processing that begins with the sensory receptors and works up to the brain's integration of sensory information.

top-down processing

Information processing guided by higher-level mental processes.

transduction

Conversion of one form of energy into another; in sensation, transforming physical energy into neural impulses.

psychophysics

The study of relationships between the physical characteristics of stimuli and our psychological experience of them.

absolute threshold

The minimum stimulus energy needed to detect a particular stimulus 50 percent of the time.

signal detection theory

A theory predicting how and when we detect the presence of a faint stimulus amid background stimulation.

subliminal

Below one's absolute threshold for conscious awareness.

priming

The activation, often unconsciously, of certain associations that predispose one's perception or response.

difference threshold

The minimum difference between two stimuli required for detection 50 percent of the time.

Weber’s law

The principle that to be perceived as different, two stimuli must differ by a constant minimum percentage.

sensory adaptation

Diminished sensitivity as a consequence of constant stimulation.

wavelength

The distance from the peak of one light wave or sound wave to the peak of the next.

hue

The dimension of color determined by the wavelength of light.

intensity

The amount of energy in a light wave or sound wave that influences what we perceive as brightness or loudness.

cornea

The eye's clear, protective outer layer.

pupil

The adjustable opening in the center of the eye through which light enters.

iris

The ring of muscle tissue that forms the colored portion of the eye and controls pupil size.

lens

The transparent structure behind the pupil that helps focus images on the retina.

retina

The light-sensitive back inner surface of the eye.

accommodation

The process by which the eye's lens changes shape to focus images.

rods

Retinal receptors that detect black, white, and gray, and are sensitive to movement.

cones

Retinal receptors concentrated near the center of the retina that detect fine detail and color.

optic nerve

The nerve that carries neural impulses from the eye to the brain.

blind spot

The point at which the optic nerve leaves the eye, creating a blind spot.

fovea

The central focal point in the retina, around which the eye's cones cluster.

Young–Helmholtz trichromatic theory

The theory that the retina contains three types of color receptors sensitive to red, green, and blue.

opponent-process theory

The theory that opposing retinal processes enable color vision.

feature detectors

Nerve cells in the brain's visual cortex that respond to specific features of a stimulus.

audition

The sense or act of hearing.

frequency

The number of complete wavelengths that pass a point in a given time.

pitch

A tone's experienced highness or lowness.

middle ear

The chamber between the eardrum and cochlea containing three tiny bones.

cochlea

A coiled, bony, fluid-filled tube in the inner ear that triggers nerve impulses.

inner ear

The innermost part of the ear, containing the cochlea and vestibular sacs.

sensorineural hearing loss

Hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerve.

conduction hearing loss

Hearing loss caused by damage to the mechanical system that conducts sound waves.

cochlear implant

A device for converting sounds into electrical signals to stimulate the auditory nerve.

place theory

In hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated.

frequency theory

In hearing, the theory that the rate of nerve impulses matches the frequency of a tone.

gate-control theory

The theory that the spinal cord contains a neurological gate that blocks or allows pain signals.

gustation

Our sense of taste.

olfaction

Our sense of smell.

kinesthesis

Our movement sense; our system for sensing the position and movement of individual body parts.

vestibular sense

Our balance sense; our sense of body movement and position that enables our sense of balance.

sensory interaction

The principle that one sense can influence another.

embodied cognition

The influence of bodily sensations, gestures, and other states on cognitive preferences and judgments.