unit 1 : 3/3

Dream

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

Sigmund Freud

Who proposed that dreams provide a psychic safety valve that discharges otherwise unacceptable feelings.

REM Rebound

Tendency for REM sleep to increase following REM sleep deprivation.

Sensation

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.

Perception

Process by which our brain organizes and interprets sensory information, enabling us to recognize objects and events as meaningful.

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, 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 physical energy, such as sights, sounds, and smells, into neural impulses the brain can interpret.

Psychophysics

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

Gustav Fechner

German scientist and philosopher who studies the edge of our awareness of these faint stimuli which he called an absolute threshold.

Absolute Threshold

Minimum stimulus energy need to detect a particular stimulus 50 percent of time.

Signal Detection Theory

Theory predicting how and when we detect the presence of a faint stimulus (signal) amid background stimulation (noise); assumes there is no single detection depends partly on person's experience, expectations, motivation, and alertness.

Subliminal

Below one's absolute threshold for conscious awareness.

Priming

Activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response.

Difference Threshold

Minimum difference between two stimuli required for detection 50 percent of the time. We experience the difference threshold as just a noticeable difference.

Ernst Weber

German physician who described a principle so simple and so widely applicable that we still refer to it as Weber's Law.

Weber's Law

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.

Wavelength

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

Hue

Dimension of color that is determined by the wavelength of light.

Intensity

Amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness. Intensity is determined by the wave's amplitude (height).

Cornea

Eye's clear, protective outer layer, covering the pupil and iris.

Pupil

Adjustable opening in the center of the eye through which light enters.

Iris

Ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of pupil opening.

Lens

Transparent structure behind the pupil that changes shape to help focus image on the retina.

Retina

Light-sensitive back inter surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information.

Accommodation

Process by which the eye's lens changes shape to focus images of near or far objects on the retina.

Rods

Retinal receptors that detect black, white, and gray, and are sensitive to movement. Rods are necessary for peripheral and twilight vision when cones don't respond.

Cones

Retinal receptors that are concentrated near the center of the retina and that function in daylight or in well-lit conditions. Cones detect fine detail and give rise to color sensations.

Optic Nerve

Nerve that carries neural impulses from the eye to the brain.

Blind Spot

Point at which the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located there.

Fovea

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

Young-Helmholtz Trichromatic (three color) Theory

Theory that the retina contains three different types of color receptors — one most sensitive to red, one to green, one to blue — which, when stimulated in combination, can produce the perception of any color.

David Hubel

Who showed that our visual processing deconstructs visual images and then reassembles them. (1979)

Torsten Wiesel

Who showed that our visual processing deconstructs visual images and then reassembles them. (1979)

Feature Detectors

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

Parallel Processing

Processing multiple aspects of a stimulus or problem simultaneously.

Audition

Sense or act of hearing.

Frequency

Number of complete wavelengths that pass a point in a given time.

Pitch

Tone's experienced highness or lowness; depends on frequency.

Middle Ear

Chamber between the eardrum and the cochlea containing three tiny bones that concentrate the vibrations of the eardrum on the cochlea's oval window.

Cochlea

Coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses.

Inner Ear

Innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs.

Sensorineural Hearing Loss

Most common form of hearing loss, caused by damage to the cochlea's receptor cells or to the auditory nerve; also called nerve deafness.

Conduction Hearing Loss

Less common form of hearing loss, caused by damage to the mechanical system that conducts sound waves to cochlea.

Cochlear Implant

Device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea.

Place Theory

In hearing, the theory that links the pitch we hear with the place where the cochlea's membrane is stimulated. (Also called pace coding.)

Frequency Theory

In hearing, the theory that the rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch. (Also called temporal coding.)

Gate-Control Theory

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

Gustation

Sense of taste

Olfaction

Sense of smell

Kinesthesis

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

Vestibular Sense

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

Sensory Interaction

Principle that one sense can influence another. Ex.When the smell of food influences its taste.

Embodied Cognition

Influence of bodily sensations, gestures, and other states on cognitive preferences and judgements.