Chapter 3

What is sensation?

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

What is perception?

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

What is transduction?

conversion of one form of energy into another; in sensation, the transforming of stimulus energies, such as sights, sounds, and smells into neural impulses our brains can interpret

What is top-down processing?

information processing guided by higher-level mental processes, as when we construct perceptions drawing on our experience and expectations

What is bottom-up processing?

analysis that begins with the sensory receptors and works up to the brain’s integration of sensory information

What is selective attention?

the focusing of conscious awareness on a particular stimulus

What is inattentional blindness?

failing to see visible objects when our attention is directed elsewhere

What is change blindness?

failing to notice changes in the environment

What is psychophysics?

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

What is an absolute threshold?

the minimum stimulation necessary to detect a particular stimulus 50% of the time

What is 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 absolute threshold and that detection depends partly on a person’s experience, expectations, motivation, and alertness

What is subliminal messaging?

below one’s absolute threshold for conscious awareness

What is priming?

the activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response

What is the difference threshold?

the minimum difference between two stimuli required for detection.  We experience the difference threshold as a just noticeable difference

What is Weber's law?

the principle that, to be perceived as different, two stimuli must differ by a constant percentage (rather than a constant amount)

What is sensory adaption?

diminished sensitivity as a consequence of constant stimulation

What is perceptual adaption?

in vision, the ability to adjust to an artificially displaced or even inverted visual field

What is perceptual set?

mental disposition to perceive one thing and not another

What is a schema?

The learned concepts with which we see the world

What is Gestalt Psychology?

an organized whole.  Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes

What is figure and ground?

The idea that we are trying to perceive the most important parts, or figures of our world. Anything beyond that becomes background

What is proximity within gestalt grouping principles?

The closer images are to each other, the more our brains interpret them as part of a group

What is similarity?

The more similar items within groups are, the more likely we are to see them as a group

What is continuity?

The habit of connecting two relatively similar objects into one grouping based on their consecutiveness

What is connectedness?

Objects moving in the same direction are considered part of the same group

What is closure?

The imagined closing of a space to create a complete shape

What are binocular cues?

depth cues, such as retinal disparity, that depend on the use of two eyes

What is convergence?

A neuromuscular cue that moves the eyes inwards for close objects and straightens them out for faraway ones

What is retinal disparity?

The difference in perception between two eyes gets corrected when viewing with both eyes but look slightly different when viewing with each eye individually

What are monocular cues?

depth cues, such as interposition and linear perspective, available to either eye alone

What is relative size?

The closer an object is, the larger it is

What is interposition?

Objects that are blocked in the visual field look further away

What is light and shadow?

The clearer an object is, the closer it seems

What is relative height?

The higher up an image is in the visual field, the further away it seems

What is texture gradient?

The closer an object is, the more texture it has

What is perceptual constancy?

perceiving objects as unchanging (having consistent shapes, size, lightness, and colour) even as illumination and retinal images change

What is depth perception?

the ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance

What is colour constancy?

based on brightness constancy and relative luminance

What is the Phi phenomenon?

an illusion of movement created when two or more adjacent lights blink on and off in quick succession

What is wavelength?

The length of a wave of energy; determines the hue of colours

What is wave amplitude?

The height of a wave; determines colour intensity (brightness)

What is the cornea?

Outer covering of the eye (protects the eye) and bends light to provide focus

What is the pupil?

the adjustable opening in the center of the eye through which lights enters

What is the lens?

the transparent structure behind the pupil that changes shape to help focus the images on the retina

What is the retina?

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

What is accommodation?

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

What are rods?

retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don’t respond

What are cones?

retinal receptors that detect black, white, and gray; necessary for peripheral and twilight vision, when cones don’t respond

What is the optic nerve?

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

What is the blind spot?

he point at which the optic nerve leaves the eye, creating a “blind” spot because no receptor cells are located there

What is the fovea?

the central focal point in the retina, around which the eye’s cones cluster

Where does information initially go in the brain after being processed by the retina?

The thalamus

What are feature detector cells?

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

What is parallel processing?

the processing of many aspects of a problem simultaneously; the brain’s natural mode of information processing for many functions, including vision; contrasts with the step-by-step (serial) processing of most computers and of conscious problem solving

What is the Young-Hemlholtz theory?

the theory that the retina contains three different 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

What is the opponent-process theory?

the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision.  For example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green

What is audition?

the sense or act of hearing

Frequency affects ___, amplitude affects ____

Pitch, volume

What is the outer ear?

The visible area of the ear, channels sound

What does the eardrum do?

Vibrates the sound into the middle ear

What is the middle ear?

the chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window

What is the cochlea?

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

What is the inner ear?

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

How do ears perceive loudness?

By the number of hair cells activated

What is place theory?

The idea that we hear different pitches because of activity triggered at different parts of the cochlea

What is 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

What is conductive hearing loss?

hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea; problems with the eardrum or three bones of the middle ear

What is sensorineural hearing loss?

hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerves; also called nerve deafness

What is a cochlear implant?

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea

What is kinaesthesis?

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

What is the vestibular sense?

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

What is 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; the “gate” is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain