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sensation

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

perception

the process of organizing and interpreting sensory info, 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 info

top-down processing

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

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

psychophysics

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

absolute threshold

the minimum stimulation 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). assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and alertness

subliminal

below one's absolute threshold for conscious awareness

priming

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

difference threshold

the minimum difference between two stimuli required for detection 50% of the time. we experience the difference threshold as a just noticeable difference (jnd)

Weber's law

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

sensory adaptation

diminished sensitivity as a consequence of constant stimulation

transduction

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

wavelength

the distance from the peak of one light or sound wave to the peak of the next. electromagnetic wavelengths vary from the short blips of cosmic rays to the long pulses of radio transmission

hue

the dimension of color that is determined by the wavelength of light

intensity

the amount of energy in a light or sound wave, which we perceive as brightness or loudness, as determined by amplitude

pupil

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

iris

a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

lens

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

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 info

accommodation

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, which, and grey; necessary for peripheral and twilight vision, when cones don't respond

cones

retinal receptor cells that are concentrated near the center of the retina and that function in daylight or in well lit conditions. detect fine detail and give rise to color sensations

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 because no receptor cells are located there

fovea

the central focus point in the retina, around which the eye's cones cluster

feature detectors

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

parallel processing

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

Young-Helmholtz trichromatic 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

opponent-process theory

the theory that opposing retinal processes (red-green, yellow-blue, white-black) enable color vision. ex: some cells are stimulated by green and inhibited by red, vice versa

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, depends on frequency

middle ear

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

cochlea

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

inner ear

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

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 traveling up the auditory nerve matches the frequency of a tone thus enabling us to sense it's pitch

conduction hearing loss

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

sensorineural hearing loss

hearing loss caused by damage to the cochlea's receptor cells or to the auditory nerves, aka nerve deafness

cochlear implant

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

kinesthesis

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

gate-control theory

the theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass 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 info coming from the brain

sensory interaction

the principle that one sense may influence another, as when the smell of food influences its taste

gestalt

an organized whole. gestalt psychologists emphasized our tendency to integrate pieces of info into meaningful wholes

figure-ground

the organization of the visual field into objects (the figures) that stand out from their surroundings (the ground)

grouping

the perceptual tendency to organize stimuli into coherent groups

depth perception

the ability to see objects in 3D although the images that strike the retina are in 2D; allows us to judge distance

visual cliff

a lab device for testing depth perception in infants and young animals

binocular cues

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

retinal disparity

a binocular cue for perceiving depth: by comparing images from the retinas in the two eyes, the brain computes distance- the greater the disparity (difference) between two images, the closer the object

monocular cues

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

phi phenomenon

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

perceptual constancy

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

color constancy

perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object

perceptual adaptation

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

perceptual set

a mental predisposition to perceive one thing and not another

extrasensory perception (ESP)

the controversial claim that perception can occur apart from sensory input, includes telepathy, clairvoyance, and precognition

parapsychology

the study of paranormal phenomena, including ESP and psychokinesis

cocktail party effect

a person's ability to single out one voice among many others, then to "change channels" to another voice. a person in a crowded, talking room can weed out other voices and converse with one person. then the first person can single out another voice and "tune in" on that person if desired

choice blindness

people's unawareness of the choices or preferences they make

pop-out

something is noticeable different than the others, thus pops out to the viewer

amplitude

refers to intensity of the wave

cornea

transparent protective coating over the front part of the eye

receptor cell

specialized cell that responds to a particular type of energy

optic chiasm

point near the base of the brain where some fibers in the optic nerve from each eye cross to the other side of the brain

colorblindness

partial or total inability to perceive hues

trichromats

people who have normal color vision

dichromats

people who are either blind to red-green or yellow-blue

hertz (Hz)

cycles per second; unit of measurement for the frequency of waves

decibel

the magnitude of a wave; in sound the primary determinant of loudness

ear canal/ auditory canal

carries sound waves into the ear

eardrum

membrane at the end of the auditory canal, vibrates due to sound waves

hammer, anvil, stirrup

the three small bones in the middle ear that relay vibrations of the eardrum to the inner ear

oval window

membrane across the opening between the middle ear and inner ear that conducts vibrations to the cochlea

round window

membrane between the middle ear and inner ear that equalizes pressure in the inner ear

basilar membrane

vibrating membrane in the cochlea of the inner ear; it contains sense receptors for sound

organ of corti

structure on the surface of the basilar membrane that contains the receptor cells for hearing

auditory nerve

the bundle of neurons that carries signals from each ear to the brain

presbycusis

occurs because of changes in the inner ear, very common that happens gradually in older age

tinnitus

people with this hear constant ringing or roaring sound. cause can't always be found- sometimes earwax, ear infections or reaction to antibiotics, many others

phantom limb sensation

the brain can produce pain in limbs that aren't even there

McGurk effect

sight and hearing go together; if we see a person say one thing but hear them say something else, the result is that we will hear a third sound that's a blend of the two

proximity

things close to one another are grouped together

similarity

things alike are grouped

continuity

we like things that are unbroken

closure

we like to complete things that are incomplete- we'll finish a circle only 90% complete

connectedness

we like things linked or brought together

relative height

things seen higher up are perceived as farther away

relative size

small things are perceived as farther away

interposition

when things are "stacked", the one that's covered up is farthest, the one that's not covered is closest

linear perspective

parallel lines, like railroad tracks, converge in the distance; the more they converge, the farther away

light & shadow

close objects reflect more light, father ones appear dimmer

relative motion

while we move, things close to us appear to move quickly in the opposite direction; things farther away appear to move very slowly or not at all

shape constancy

tendency to expect things to retain their shape

size constancy

tendency to expect things to retain their size