Chapter 3

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

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

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

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

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

the focusing of conscious awareness on a particular stimulus

failing to see visible objects when our attention is directed elsewhere

failing to notice changes in the environment

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

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

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

below one’s absolute threshold for conscious awareness

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

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

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

diminished sensitivity as a consequence of constant stimulation

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

mental disposition to perceive one thing and not another

The learned concepts with which we see the world

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

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

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

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

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

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

The imagined closing of a space to create a complete shape

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

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

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

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

The closer an object is, the larger it is

Objects that are blocked in the visual field look further away

The clearer an object is, the closer it seems

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

The closer an object is, the more texture it has

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

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

based on brightness constancy and relative luminance

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

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

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

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

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

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

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

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

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

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

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

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

The thalamus

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

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

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

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

the sense or act of hearing

Pitch, volume

The visible area of the ear, channels sound

Vibrates the sound into 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

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

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

By the number of hair cells activated

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

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

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

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

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

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

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

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