Unit 4: Sensation & Perception Flashcards
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 information, allowing us to recognize important objects and events
sensory receptors
sensory nerve endings that respond to stimuli
bottom-up processing
beginning with the sensory input, the brain attempts to comprehend from there
top-down processing
led by experiences and higher-level processes, we comprehend what our brains are familiar with and what we want to see
selective attention
our tendency to focus on just a particular stimulus among the many that are being received; although we are surrounded by sights and sounds, smells and tastes, we tend to pay attention to only a few at a time
inattentional blindness
failing to see visible objects when our attention is directed elsewhere
cocktail party effect
the ability to focus your attention on one particular voice in hubbub, a great example of selective attention
change blindness
failing to notice changes in the visual environment
transduction
conversion of one form of energy, such as light waves, into another form, like neural impulses that our brain is able to interpret
What is the transduction process?
a. receive sensory information
b. transform the stimulation into neural impulses
c. deliver the neural information to the brain for processing
psychophysics
the study of relationships between the physical characteristics of stimuli, such as their intensity, and our psychological experience of them
absolute threshold
the minimum stimulus energy needed to detect a particular stimulus 50% of the time
signal detection theory
a theory predicting how and when we predict weak signals; this theory assumes that there is no single absolute threshold and that detection depends partly on a person’s experiences and expectations
subliminal
below one’s absolute threshold for conscious awareness
difference threshold
the minimum difference between two stimuli required for detection 50% of the time
priming
the action, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response
Weber’s law
to be perceived as different, two stimuli must differ by a constant minimum percentage, rather than a constant amount
sensory adaptation
diminished sensitivity as a consequence of constant stimulation
perceptual set
a mental predisposition to perceive one thing and not another; we see what we expect to see
extrasensory perception (ESP)
the controversial claim that awareness can occur partly from sensory input; includes telepathy (mind-to-mind communication), clairvoyance (seeing remote things), and precognition (seeing the future)
parapsychology
the study of paranormal phenomena, including ESP and psychokinesis (the ability of the mind to move objects)
wavelength
the distance from the peak of one light or sound wave to the peak of the next
hue
the dimension of color that is determined by the wavelength of the light; colors like blue, red, green, etc.
intensity
the amount of energy in a light wave or sound wave, which influences what we perceive as brightness or loudness; intensity is determined by the wave’s amplitude
cornea
the eye’s clear, protective outer layer covering the pupil and iris; light enters the eye first through the cornea
pupil
a small adjustable opening in the center of the eye through which light passes
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 by expanding and contracting over the pupil
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 + layers of neurons that begin the processing of visual information
accommodation
the process of lens changing its curvature to focus the rays
rods
retinal photoreceptors on the side of the eye that detect black, white, and gray and are sensitive to movement; responsible for peripheral vision
cones
retinal photoreceptors that are concentrated near the center of the retina and function in daylight or in well-lit conditions; detects fine detail and create color sensations
optic nerve
the nerve that carries neural impulses from the eye to the brain; comprised of the axons of the ganglion cells
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 focal part in the retina around which the eye’s cones cluster; this is the area of greatest visual focus
Young-Helmholtz Trichromatic Theory
the theory that the retina contains three different types of color receptors (cones) – one most sensitive to red, one to blue, and one to green– which, when stimulated, can produce the perception of any color
colorblindness
often lacking red and/or green-sensitive cones: vision is monochromatic and or dichromatic and seems ‘normal’ to them; hereditary
opponent-process theory
the theory that cone photoreceptors are paired together (red-green, blue-yellow, white-black) to enable color vision; activation of one color of the pair inhibits activation
feature detectors
bundles of nerve cells located in the visual cortex of the occipital lobe that responds to a scene’s edges, lines, angles, and movements
parallel processing
thinking about many aspects of a problem simultaneously; different areas process motion, form, depth, and color and then compile these to on perceived image
Gestalt
a German word meaning a “form” or a “whole”; German psychologists noticed that people who are given a cluster of sensations tend to organize them into these forms; Gestalt psychologists believe that in perception, the whole may exceed the sum of its parts; we filter incoming information and construct our perceptions
figure-ground
the organization of the visual field into objects that stand out from their surroundings
grouping
our mind brings order and form to stimuli by following certain rules for grouping; these rules illustrate how the perceived whole differs from the sum of its parts
depth perception
the ability to see objects in three dimensions although the images that strike the retina are two-dimensional, this allows us to judge distance
–> sets in when babies begin to crawl
visual cliff
Eleanor Gibson and Richard Walk (1960) designed a series of experiments in their Cornell University laboratory using a visual cliff, a model of a cliff with a “drop-off” area that was covered by glass to test babies’ depth perception
binocular cue
depth cues that depend on the use of both eyes; as an object becomes closer or father, both binocular depth cues operate to help us judge distance
retinal disparity
by comparing the retinal images from the two eyes, the brain computes distance; the greater the difference between the two images, the closer the object
monocular cue
depth cues available to each eye separately when there isn’t different retinal images between our two eyes
relative height
we perceive objects higher in our field of vision as father away
relative size
if we assume two objects are similar in size, most people perceive the one that casts the smaller retinal image as farther away
interposition
if one object partially blocks our view of another, we perceive it to be closer
relative motion
as we move, objects that are actually stable may appear to move
ex: a person on a train might see passing homes as appearing to move, though the train is the object actually moving
linear perspective
a type of depth prompt that the human eye perceives while viewing two parallel lines that appear to meet at a distance
ex: when a long stretch of highway is seen by the human eye, the lanes seem to join together on the horizon.
Phi phenomenon
our brain perceives a rapid series of slightly varying lights as continuous movement and constructs this movement in our heads
ex: when we perceive two adjacent stationary lights blinking on and off in quick succession as one single light moving back and forth
perceptual constancy
a top-down process that recognizes objects without being deceived by changes in their color, brightness, shape, or size
color constancy
perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object
shape constancy
perceiving an object as having an unchanging shape, even while our distance from it varies
perceptual adaptation
the ability to adjust to changed sensory input, including an artificially displaced or even inverted visual field
audition
the sense or act of hearing
frequency
the number of complete wavelengths that pass a point in a given time, like per second
pitch
a tone’s experienced highness or lowness, depending on frequency
middle ear
contains the eardrum and significant bones of the organ, the ossicles
cochlea
a coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlea fluid trigger neural responses
inner ear
contains the cochlea, the auditory nerve, and the semicircular canals that control balance
sensorineural hearing loss
damage to the cochlea’s hair cell (cilia) receptors or the auditory nerve; those who experience this may hear sound but have trouble discerning what is being said
conduction hearing loss
damage to the eardrum and middle ear bones that conducts sound waves to the cochlea; less common than sensorineural hearing loss
cochlear implant
translates sounds into electrical signals that are transmitted to the cochlea, and, via the auditory nerve, relayed to the brain
place theory
… presumes that we hear different pitches because different sound waves trigger activity at different spots along the cochlea’s basilar membrane: the brain determine’s a sound’s pitch by recognizing the specific area or membrane that is generating the neural signal
frequency theory (temporal theory)
suggests the brain reads pitch by monitoring the frequency of neural impulses traveling up the auditory nerve; the whole basilar membrane vibrates with the incoming sound wave, triggering neural impulses to the brain at the same time as the sound wave
pain
a biopsychosocial experience; in a pain circuit, sensory receptors respond to potentially damaging stimuli by sending an impulse to the spinal cord, which passes the message in the brain, which interprets the signal as pain
gate-control theory
states 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 (like soreness) and is closed by activity in larger nerve fibers (like a massage) or by information coming from the brain (like distracting thoughts)
taste/gustation
on the top and sides of one’s tongue are 200 or more taste buds, each containing a pore that catches food chemicals
smell/olfaction
we smell something when molecules of a substance carried in the air reach a tiny cluster of receptor cells at the top of each nasal cavity; is the only sense to NOT pass neural information through the thalamus
synesthesia
in select individuals, the brain circuits for two or more senses become joined, and the stimulation of one sense, like hearing sound, triggers the experience of another, like seeing color; synesthetes may hear music as color or experience numbers as tastes
kinesthetic sense
position and motion detectors in muscles, tendons, and joints sense the position and movement of body parts
vestibular sense
fluid-filled semicircular canals and a pair of calcium-crystal filled vestibular sacs located in the ears monitor the head’s and body’s movements
sensory interaction
our senses influencing each other
ex: how when we have a cold, food tends to have less flavor –> smell affecting taste
embodied cognition
the influence of bodily sensations, gestures, and other states on cognitive preferences and judgements
Gustav Fechner
German scientist and philosopher who demonstrated the non-linear relationship between psychological sensation and the intensity of a stimuli –> absolute threshold
David Hubel
with Weisel, discovered how the visual system builds an image from simple stimuli into more complex representations in information processing –> feature detectors
Harry McGurk
discovered the phenomenon of the impact of visual cues on speech perceptions, particularly the identification of spoken syllables
Ernst Weber
German physician who is considered one of the founders of experimental psychology; his studies on the sense of touch introduced the concept of the difference threshold that future psychologists would research further
Torsten Wiesel
with Hubel, discovered how the visual system builds an image from simple stimuli into more complex representations in information processing –> feature detectors
