ch4 sensation and perception

sensation

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

• light and sound waves

perception

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

• how you react to sensory patterns

bottom-up processing

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

• no prior knowledge, start from the bottom and go up

top-down processing

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

• have prior knowledge, work to process details

selective attention

the focusing of conscious awareness on a particular stimulus

• very broad

inattentional blindness

failing to see visible objects when our attention is directed elsewhere

• focus changes to something else, focus changes to your phone rather then the road when driving

change blindness

failing to notice changes in the environment

• too preoccupied or focused on something else to not notice a change

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 brain can interpret

• begins with the detection by a sensory neuron

psychophysics

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

absolute threshold

the minimum stimulation needed to detect a particular stimulus 50 percent of the time

signal detection theory

a theory predicting how ad when we detect the presence of a faint stimulus amid background stimuluation

• depends on experience and expectations

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 percent of the time

Weber’s law

the principal that, to be perceived as different, two stimuli must differ by a constant minimum percentage

sensory adpation

diminished sensitivity as a consequence of constant stimulation

• smelling a candle when you first walk in a room, but then getting used to it and not noticing the smell anymore

perceptual set

a mental predisposition to perceive one thing and not another

• similarity effects taste

extrasensory perception

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

parapsychology

the study of paranormal phenomena, including ESP and psychokinesis

just noticbiable difference

the minimal amount of change in the signal that is still recognizable

• dimming the lights in a bedroom

wavelength

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

• color for vision and pitch for sound

hue

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

• colors

intensity

the amount of energy in a light or sound wave , which we perceive as brightness or loudness, as determined by the wave’ s 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 ad 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 payers of neurons that begin the processing of visual information

accommodation

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

rods

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

• only good for peripheral vision

cones

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

• detect color

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 reina, around whihc the eye’s cones cluster

• area with the sharpest vision rods and cones are the most concentrated

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

young-helmholtz trichromatic theory

the theory that the retina contains three different color receptors

• cones detect colors

opponent process theory

the theory that opposing retinal processes enable color vision

gestalt

an organized whole… empathized our tendency to integrate pieces of information into meaningful wholes

• similarity, proximity, continuity, closure

figure-ground

the organization of the visual field into objects that stand out from their surroundings

• the back ground and the physical figure

grouping

the perceptual tendency to organize stimuli into coherent groups

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

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

• two eyes

retinal disparity

a binocular cue for perceiving depth… comparing images from the retinas in the two eyes, the brain can compute the distance

monocular cues

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

• one eye

phi phenomenon

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

perceptual constancy

perceiving objects as unchanging 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

audition

the sense or act of hearing

frequency

the number of complete wavelengths that pass a point in a given time

• length

pitch

a tone’s experienced highness or lowness; depends on the frequency

middle ear

the chamber between the eardrum and cochlea containing three tiny bones that concentrate on the vibrations of the eardrum on the cochlea’s oval window

cochlea

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

inner ear

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

sensorninerual hearing loss

hearing loss caused by damage to the cochlea’s receptor cells OR to the auditory nerves

conduction hearing loss

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

place theory

in hearing, the theory that links the pitch we hear w/ the place where the cochlea’s membrane is stimulated

frequency theory

in hearing, the theory that the rate of the nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabaling us to sense its pitch

gate control theory

the theory that the spinal cord contains a neurological ‘gate"‘ that blocks pain signals or allows them to pass onto the brain. this is opened by activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by incoming information.

kinesthesia

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.

sensory interaction

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

• two senses interact and affect one anothers perception

embodied cognition

in psychological science, the influence of bodily sensations, gestures, and other states on cognitive preferences and judgments