Unit 4 - Sensation & Perception Flashcards
What is an example used to describe the difference between sensation and perception?
prosopagnosia - perfect vision allows sensory receptors to detect the same information as anybody else (sensation) while the organization and interpretation of sensory information does not enable her to recognize objects (perception)
prosopagnosia
face blindness; the inability to recognize faces; similar to trying to recognize a specific penguin in a group of waddling penguins
sensation & perception
1) How do we construct our representations of the external world?
2) How does a campfire specifically activate neural connections?
3) How do we create our conscious experience of the outside world?
the brain & perception
the mind interprets what the senses detect
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, 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 information
attention
it’s harder to focus attention than it is to divide it; at any precise moment, it is in one place
conscious & unconscious awareness
we are “blind” to all but a tiny sliver of the immense array of visual stimuli constantly before us
five senses take in 11,000,000 bits of information per second, but the mind consciously perceives about 40 bits; the mind’s unconscious track perceives the other 10,999,960 bits
cocktail party effect
the ability to attend to only one voice among many
change deafness
failing to notice changes in the environmental sound; 40% of people focused on repeating a list of sometimes challenging words failed to notice a chance in the person speaking
choice blindness
failing to notice the deception of their choice; choose between two female faces, have the experimenter switch the photos, and the volunteer does not notice and/or acknowledge the switch
choice-blindness blindness
pop-out
stimuli that is so strong that it draws the eyes and demands our attention
only smiling face in a crowd of frowning faces
top-down processing
information processing guided by 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
subliminal stimuli
stimuli we detect less than 50% of the time
below one’s absolute threshold for conscious awareness
sometimes we feel what we do not know and cannot describe
information processing
much of our information processing occurs automatically, out of sight, off the radar screen of our conscious mind
hidden persuasian
the stimulus has no direct effect, but people perceive themselves receiving the benefits they expect
inattentional blindness
failing to see visible objects when our attention is directed elsewhere
change blindness
failing to notice changes in the environment
reducing sensitivity
gives us the freedom to focus on informative changes in our environment without being distracted by the constant chatter of uninformative background stimulation
perception of the world
we perceive the world not exactly as it is, but as it is useful for us to perceive it
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 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
military personnel detecting nearly imperceptible noises
masking stimulus
a stimuli that interrupts the brain’s processing before conscious perception
image that follows adorable kitten while be described in a much nicer way than if it was followed by a scary scene
priming
the activation, often unconsciously, of certain associations, thus predisposing one’s perception, memory, or response
difference threshold (just noticeable difference)
the minimum difference between two stimuli required for detection 50% of the time; we experience the difference threshold as a just noticeable difference (jnd)
lights - 8%
objects - 2%
tones (frequency) - 0.3%
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
after constant exposure, nerve cells fire less frequently
walking into a room with a musty odor and then no longer noticing it minutes later
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 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; what we know as the color names blue, green, and so forth
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 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 information
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, white, and gray; 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; the cones detect fine detail and gives rise to color sensations
optic nerve
the nerve that carries neural impulses from the eye to the brain
blind point
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 point in the retina, around which the eye’s cones cluster
cornea
protects the eye and bends light to provide focus
parallel processing
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
Young-Helmholtz Trichromatic (three-color) Theory
the theory that the retina contains three different color receptors - one most sensitive to red, one to green, one to blue - which, when simulated 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; for example, some cells are stimulated by green and inhibited by red; others are stimulated by red and inhibited by green
audition
the sense or act of hearing
frequency
the number of complete wavelengths that pa a point in a given time (for example, per second)
pitch
a tone’s experienced highness or lowness; depends on frequency
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
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
feature detectors
nerve cells in the brain that responds to specific features of the stimulus, such as shape, angle, or movement
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 its 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; also called nerve deafness
cochlear implant
a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea
stereophonic hearing
three dimensional hearing caused by the “surround-sound” effect of two ears on each side of the head
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 block pain signals or allow them to pass on to the brain. The “gate” i opened by the activity of pain signal traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain
nociceptors
sensory receptors that detect hurtful temperature, pressure, or chemicals
sensory interaction
the principle that one sense may influence another, as when the smell of food influences its taste
smell + texture + taste = flavor
gestalt
an organized whole. Gestalt psychologists emphasized our tendency to integrate pieces of information into meaningful wholes
figure-ground
the organization of the visual field into objects (the figures) that stand out from their surrounding (the ground)
proximitely
we group nearby figures together
three sets of two lines, rather than six separate lines
continuity
we perceive smooth, continuous patterns rather than discontinuous ones
a series of alternating semicircles is perceived a two continuous lines - one wavy, one straight
connectedness
uniform and linked
perceive each set of two dots and the line between them as a single unit
closure
we fill in gaps to create a complete, whole object
we assume that the circles are completely but partially blocked by the (illusory) triangle. Add nothing more than little line segments that close off the circles and now your brain stops constructing a triangle
similarity
we group similar figures together
vertical columns of triangles and circles, rather than horizontal row of dissimilar shapes
monocular cues
depth cues, such as interposition and linear perspective, available to either eye alone
phi phenomen
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
lightness (brightness) constancy
we perceive an object as having a constant lightness even while its illumination varies
relative luminance
the amount of light an object reflects relative to its surroundings
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
schemas
concepts that organize and interpret unfamiliar information
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 pychokinesis
grouping
the perceptual tendency to organize stimuli into coherent group
depth perception
the ability to see objects in three dimension although the images that strike the retina are two-dimensional; allows us to judge distance
visual cliff
a laboratory 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 the two images, the closer the object
