Mastering the World of Psychology Chapter 3

sensation

the process through which the senses pick up visual, auditory, and other sensory stimuli and transmit them to the brain

perception

the process by which the brain actively organizes and interprets sensory information

absolute threshold

the minimum amount of sensory stimulation that can be detected 50% of the time

difference threshold

a measure of the smallest increase or decrease in a physical stimulus that is required to produce a difference in the sensation that is noticeable 50% of the time

just noticeable difference (JND)

the smallest change in sensation that a person is able to detect 50% of the time

Weber's law

the law stating that the just noticeable difference (JND) for all the senses depends on a proportion or percentage of change in a stimulus rather than a fixed amount of change

sensory receptors

highly specialized cells in the sense organs that detect and respond to one type of sensory stimulus -- light, sound, or odor, for example -- and transduce (convert) the stimuli into neural impulses

transduction

the process through which sensory receptors convert the sensory stimulation into neural impulses; provide link between the physical sensory world and the brain

sensory adaptations

the process in which sensory receptors grow accustomed to constant, unchanging levels of stimuli over time

visible spectrum

the narrow band of light waves that are visible to the human eye

wavelength

a measure of distance from the peak of a light wave to the peak of the next

cornea

the tough, transparent, protective layer that covers the front of the eye and bends light rays inward through the pupil

lens

the transparent disk-shaped structure behind the iris and the pupil that changes shape as it focuses on objects at varying distances

accommodation

the flattening and bulging action of the lens as it focuses images of objects on the retina

retina

the layer of tissue that is located on the inner surface of the eyeball and contains the sensory receptors for vision

rods

the light-sensitive receptor cells in the retina that look like slender cylinders and allow the eye to respond to a few as five photons of light

cones

the light-sensitive receptor cells in the retina that enable humans to see color and the fine detail in adequate light but do not function in very dim light

fovea

a small area at the center of the retina that provides the clearest and sharpest vision because it has the largest concentration of cones

blind spot

the point in each retina where there are no rods or cones because the cable of ganglion cells is extending through the retinal wall

optic nerve

the nerve that carries visual information from each retina to both sides of the brain

primary visual cortex

the part of the brain in which visual information is processed

feature detectors

neurons in the brain that respond only to specific visual patters (for example, to lines or angles)

hue

the dimension of light that refers to the specific coor perceived

saturation

the purity of a color, or the degree to which the light waves producing it are of the same wavelength

brightness

the intensity of the light energy perceived as a color; based on amplitude of light wave

trichromatic theory

the theory of color vision suggesting that three types of cones in the retina each make a maximal chemical response to one of three colors -- blue, green, or red

opponent-process theory

the theory of color vision suggesting that three kinds of cells respond by increasing or decreasing their rate of firing when different colors are present

afterimage

a visual sensation that remains after a stimulus is withdrawn

color blindness

the inability to distinguish certain colors from one another

frequency

the number of cycles completed by a sound wave in one second, determining the pitch of the sounds; expressed in the unit called the hertz

amplitude

the measure of loudness of a sound; expressed in the unit called the decibel

decibel (dB)

the unit of measurement for the loudness of sounds

timbre

the distinctive quality of a sound that distinguishes it from other sounds of the same pitch and loudness

different between optometrist and ophthalmologist

optometrist- MD

ophthalmologist- OD

iris

colored part of the eye, control light levels inside the eye similar to the aperture on a camera

pupil

round opening n the center of the iris

audition

the sensation and process of hearing

outer ear

the visible part of the ear, consisting of the pinna and the auditory canal

middle ear

the portion of the ear containing the ossicles, which connect the eardrum to the oval window and amplify sound waves

inner ear

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

cochlea

the fluid-filled, snail-shaped, bony changer in the inner ear that contains the basilar membrane and its hair cells (the sound receptors)

hair cells

sensory receptors or hearing that are attached to the basilar membrane in the cochlea

place theory

the theory of hearing that holds that each individual pitch a person hears is determined by the particular location along the basilar membrane of the cochlea that vibrates the most

frequency theory

the theory of hearing that holds that hair cells receptors vibrate the same number of times per second as the sounds that reach them

kinesthetic sense

the sense providing information about the position and movement of body parts

vestibular sense

the sense that provides information about the body's orientation in space

olfactory epithelium

two 1-square-inch patches of tissue, one at the top of each nasal cavity, which together contain about 10 million olfactory neurons, the receptors for smell

olfactory bulbs

two matchstick-sized structures above the nasal cavities, where the smell sensations first register in the brain

olfaction

the sense of smell

gustation

the sense of taste

taste buds

structures along the sides of many of the tongue's papillae that are composed of 60 to 100 receptor cells for taste

tactile

pertaining to the sense of touch

endorphins

the body's own natural painkillers, which block pain and produce a felling of well-being

attention

the process of sorting through sensations and selecting some of them for further processing

inattentional blindness

the phenomenon in which we shift our focus from one object to another and, in the process, fail to notice changes in objects to which we are not directly paying attention

cross-modal perception

a process whereby the brain integrates information from more than one sense

bottom-up processing

information processing in which individual components or bits of data are combines until a complete perception is formed

top-down processing

information processing in which precious experience and conceptual knowledge are applied to recognize the whole of a perception and thus easily identify the simpler elements of that whole

perceptual set

an expectation of what will be perceived, which can affect what actually is perceived

mirror neuron system (MNS)

a network of cells that the brain uses to interpret and produce motor actions and emotion-related behavior

Gestalt

a German word that roughly refers to the whole form, pattern, or configuration that a person perceives

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perceptual constancy

the phenomenon that allows us to perceive objects as maintaining stable properties, such as size, shape, and brightness, despite differences in distance, viewing angle, and lighting

depth perception

the ability to perceive the visual world in three dimensions and to judge distances accurately

binocular depth cues

depth cues that depend on both eyes working together

monocular depth cues

depth cues that can be perceived by on eye alone

illusion

a false perception or a misperception of an actual stimulus in the environment

subliminal perception

the capacity to perceive and respond to stimuli that are presented below the threshold of awareness

extrasensory perception (ESP)

gaining information about objects, events, of other person's thoughts through some means other than the known sensory channels

synesthesia

the capacity for experiencing unusual sensations along with ordinary ones