unit 1b psych tings

Consciousness

Our subjective awareness of ourselves and our environment.

Cognitive Neuroscience

The interdisciplinary study of the brain activity linked with cognition (including perception, thinking, memory, and language).

Selective Attention

The focusing of conscious awareness on a particular stimulus.

Inattentional Blindness

Failing to see visible objects when our attention is directed elsewhere.

Change Blindness

Failing to notice changes in the environment; a form of inattentional blindness.

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 many aspects of a problem simultaneously; the brain's natural mode of information processing for many functions.

Sequential Processing

Processing one aspect of a problem at a time; generally 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 (for example, of temperature and wakefulness) that occur on a $24\text{-hour}$ cycle.

REM Sleep

Rapid eye movement sleep; a recurring sleep stage during which vivid dreams commonly occur. Also known as paradoxical sleep, because the muscles are relaxed (except for minor twitches) but other body systems are active.

Alpha Waves

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

Delta Waves

The large, slow brain waves associated with deep sleep.

Hallucinations

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

Suprachiasmatic Nucleus

A pair of cell clusters in the hypothalamus that controls circadian rhythm. In response to light, it causes the pineal gland to adjust melatonin production, modifying feelings of sleepiness.

Insomnia

Recurring problems in falling or staying asleep.

Narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks. The sufferer may lapse directly into REM sleep, often at inopportune times.

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; unlike nightmares, these occur during NREM-3 sleep, within two or three hours of falling asleep, and are seldom remembered.

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 (as distinct from its latent, or hidden, content).

Latent Content

According to Freud, the underlying meaning of a dream (as distinct from its manifest content).

REM Rebound

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

REM Sleep Behavior Disorder

A condition in which normal REM paralysis does not occur; instead, twitching, walking, talking, kicking, punching, and acting out dreams can occur.

Psychoactive Drug

A chemical substance that alters perceptions and moods.

Substance Disorder

A disorder characterized by continued substance craving and use despite significant life disruption and/or physical risk.

Sensation

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

Sensory Receptors

Sensory nerve endings that respond to stimuli.

Gustation

Our sense of taste.

Perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

Bottom-Up Processing

Analysis 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, as when we construct perceptions drawing on our experience and expectations.

Transduction

Conversion of one form of energy into another. In sensation, the transforming of stimulus energies into neural impulses our brain can interpret.

Psychophysics

The study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them.

Absolute Threshold

The minimum stimulus energy needed to detect a particular stimulus $50\%$ of the time.

Signal Detection Theory

A theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise), assuming detection depends partly on a person's experience, expectations, motivation, and alertness.

Difference Threshold

The minimum difference between two stimuli required for detection $50\%$ of the time; experienced as a just noticeable difference (jnd).

Subliminal

Below one's absolute threshold for conscious awareness.

Priming

The activation, often unconsciously, of certain associations, predisposing one's perception, memory, or response.

Weber's Law

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

Sensory Adaptation

Diminished sensitivity as a consequence of constant stimulation.

Perceptual Set

A mental predisposition to perceive one thing and not another.

Wavelength

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

Hue

The dimension of color that is determined by the wavelength of light; what we know as color names such as blue or green.

Intensity

The amount of energy in a light wave or sound wave, which influences perceived brightness or loudness, determined by the wave's amplitude.

Retina

The light-sensitive inner surface of the eye, containing receptor rods and cones plus layers of neurons that begin visual processing.

Accommodation (Of the eye)

The process by which the eye's lens changes shape to focus near or far objects on the retina.

Rods

Retinal receptors that detect black, white, and gray, and are sensitive to movement; necessary for peripheral and twilight vision.

Cones

Retinal receptors concentrated near the center of the retina that function in daylight or well-lit conditions to 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 an area where no receptor cells are located.

Fovea

The central focal point in the retina, around which retinal cones cluster.

Young-Helmholtz Trichromatic Theory

The theory that the retina contains three different types of color receptors—most sensitive to red, green, and blue—which together produce the perception of any color.

Opponent-Process Theory (Of color)

The theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.

Feature Detectors

Nerve cells in the brain that respond to specific features of a stimulus, such as shape, angle, or movement.

Gestalt

An organized whole; emphasizes our tendency to integrate pieces of information into meaningful wholes.

Figure-Ground

The organization of the visual field into objects that stand out from their surroundings.

Grouping

The perceptual tendency to organize stimuli into coherent groups.

Depth Perception

The ability to see objects in three dimensions although the images that strike the retina are two-dimensional, allowing distance judgment.

Visual Cliff

A laboratory device for testing depth perception in infants and young animals.

Binocular Cue

A depth cue, such as retinal disparity, that depends on the use of two eyes.

Monocular Cue

A depth cue, such as interposition or linear perspective, available to either eye alone.

Perceptual Constancy

Perceiving objects as unchanging (consistent color, brightness, shape, and size) even as illumination and retinal images change.

Perceptual Adaptation

The ability to adjust to changed sensory input, including an artificially displaced or inverted visual field.

Audition

The sense or act of hearing.

Frequency

The number of complete wavelengths that pass a point in a given time (for example, per second).

Pitch

A tone's experienced highness or lowness, which depends on frequency.

Cochlea

A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses.

Sensorineural Hearing Loss

Hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves; also called nerve deafness.

Conduction Hearing Loss

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

Place Theory

In hearing, the theory that links pitch with the specific location where the cochlea's membrane is stimulated.

Frequency Theory

In hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone; also called temporal theory.

Gate-Control Theory

The theory that the spinal cord contains a neurological gate that blocks pain signals or allows them to pass on to the brain.

Olfaction

The sense of smell.

Kinesthesia

The system for sensing the position and movement of individual body parts.

Vestibular Sense

The sense of body movement and position, including the sense of balance.

Sensory Interaction

The principle that one sense may influence another, such as when smell affects taste.

Embodied Cognition

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