U5: Sensation and Perception Flashcards
sensation
relationship between physical stimulation and its psychological effect
perception
the way we recognize, interpret, and organize our sensations
absolute threshold
the minimal amount of stimulation needed to detect a stimulus and cause the neuron to fire 50% of the time
signal detection theory (SDT)
the signal (stimulus) is either present or it is not, and the participants respond that they can detect a signal or they cannot. There are the following four possibilities: hit, miss, false alarm, and correct rejection
hit
the signal was present, and the participant reported sensing it
miss
the signal was present, but the participant did not sense it
false alarm
the signal was absent, but the participant reported sensing it
correct rejection
the signal was absent, and the participant did not report sensing it
weber’s law
the greater the magnitude of the stimulus the larger the differences must be to be noticed
discrimination threshold
the point at which one can distinguish the difference between two stimuli
just noticeable difference (JND)
the minimum about of distance between two stimuli that can be detected as distinct
subliminal perception
form of preconscious processing that occurs when we are presented with stimuli so rapidly that we are not consciously aware of them
priming
preconscious processing
tip-of-the-tongue phenomenon
preconscious information processing, where we try to recall something that we already know is available but is not easily available for conscious awareness
receptor cells
specialized cells in sensory organs, designed to detect specific types of energy
receptive field
area in which our receptor cells receive input
transduction
the process where the receptors convert the input, or stimulus, into neural impulses that are sent to the brain
contralateral shift
happens at the thalamus, where much of the sensory input from one side of the body travels to the opposite side of the brain
sensory coding
process which receptors convey such a range of information to the brain
qualitative and quantitative dimensions
every stimulus has two dimensions: qualitative and quantitative
qualitative dimensions: what it is
quantitative dimensions: how much of it there is
visual sensation
occurs when the eye receives light input from the outside world
distal stimulus
the object as it exists in the environment
proximal stimulus
the image of the object on the retina
cornea
light first passes through the cornea
cornea: the protective layer on the outside of the eye
lens
- just under the cornea
- curvature of the lens accommodates for distance
accommodation
the changes of the lens curvature to accommodate for distance
retina
- at the back of the eye
- the screen which the proximal stimulus is projected
- covered with receptors (rods and cones)
rods
- located on the periphery of the retina
- sensitive in low light
cones
- concentrated in the center of the retina (fovea)
- sensitive to bright light and color vision
fovea
center of the retina
bipolar and amacrine cells
- after light stimulates the receptors, info passes through these horizontal cells
- low level processing may occur
optic nerves
- after retina and bipolar and amacrine cells, stimulation travels to optic nerve’s ganglion cells
- optic nerves cross at the optic chiasm
optic chiasm
at optic chiasm, the information from each visual field is sent to the opposite side of the brain
serial processing
when the brain computes information step-by-step in a methodical and linear matter
parallel processing
when the brain computes multiple pieces of information simultaneously (what happens when visual info reaches the visual cortex)
feature detector neurons
see different parts of the patterns (i.e. lines set at a specific angle to the background)
convergence
process where as information moves forward, it becomes more complex and integrated (happens in all sensory systems)
young-helmholtz/trichromatic theory
the cones in the retina of eyes are activated by light waves associated wit blue, red, and green; we see all colors by mixing the three
opponent process theory
cells within the thalamus respond to opponent parts of receptor sets (black/white, red/green, and blue/yellow); if one color is activated, the other is turned off
after image
when you stare at a red dot and then you turn away to a blank page and see a green dot
color blindness
happens mostly in males (sex linked)
dichromats
people who cannot distinguish along red/green or blue/yellow continuums
monochromats
see only in shade of black and white (rare)
Auditory Input
sound waves that enter the ear by passing through the outer ear and into ear canal
Tympanic Membrane
abuts the ossicles and vibrates them
ossicles
three tiny bones that comprise the middle ear
stapes
last of 3 ossicles, vibrates against oval window
oval window
beginning of inner ear
cochlea
produces nerve impulses in response to sound vibrations
vestibular sacs
balance, contains receptors sensitive to tilting
place theory
asserts that sound waves generate activity at different places along the basilar membrane
frequency theory
states that we can sense pitch because the rate of neural impulses is equal to the frequency of a particular sound
deafness
damage to ear structure or the neural pathway
conductive deafness
injury to the outer or middle ear structures (ex. the eardrum)
sensorineural/nerve deafness
impairment of some structures from the cochlea to the auditory cortex.
Olfaction
smell, scent molecules contact receptor cells at olfactory epithelium. axons from these receptors go to olfactory bulbs in brain. then info travels to olfactory cortex and limbic system.
gustation
taste, papillae contains taste buds (receptors)
cutaneous & tactile receptors
provide info about pressure, pain and temp.
c fibers
unmyelinated and responsible for throbbing sense of pain
a delta fibers
myelinated, sent info about acute pain
“pain gating”
process that reduces the intensity of pain signals. a signal is sent from the brain to opiate receptors in the spinal cord, reducing the sensation of pain
cold fibers
receptor cell for temp. that fires in response to cold stimuli
warm fibers
receptor cell for temp. that are sensitive to warm stimuli
vestibular sense
sensation of balance, located in semicircular canals of the inner ear
kinesthesis
found in joints and ligaments, transmits info about the location and position of the limbs and body parts
adaptation
unconscious, temporary change in response to environmental stimuli (ex. adjusting to darkness)
habituation
process by which we become accustomed to a stimulus and notice it less and less over time
dishabituation
occurs when a change in the stimulus causes us to notice it again
attention
the processing through cognition of a select portion of the massive amount of information incoming from the senses and contained in our memory
selective attention
when we try to attend to one thing while ignoring another
“cocktail party phenomenon”
our ability to carry on and follow a conversation in a room full of conversations
shadowing
the repetition of only one conversation
filter theories
propose that stimuli must pass through some form of screen or filter to enter into attention
attentional resource theories
propose that we have only a fixed amount of attention and this resource can be divided up as is required in a given situation
divided attention
trying to focus on more than one task at a time
perceptual processes
how our mind interprets stimuli
bottom up processing
achieves recognition of an object by breaking it down into its component parts, relying heavily on sensory receptors
top down processing
occurs when the brain labels a particular stimulus or experience
visual perception
the ability to interpret the surrounding environment using light in the visible spectrum reflected by the objects in the environment
monocular depth cues
cues that we need only one eye to see (2D)
relative size
the fact that images that are farther from us project a smaller image on the retina than do those that are closer to us
texture gradient
the distortion in size which closer objects have compared to objects farther away
interposition
occurs when a near object partially blocks the view of an object behind it
linear perspective
a monocular cue based on the perception that parallels lines seem to draw closer together as the lines recede into the distance
vanishing point
point at which two lines become indistinguishable from a single line and then disappear
aerial perspective
observation that atmospheric moisture and dust tend to obscure objects in the distance more than they do nearby objects (driving in fog and building is clearer and clearer as you drive closer)
relative clarity
less distinct, fuzzy images appear to be more distant
motion parallax
difference in apparent movement of objects at different distances, when the observer is in motion
Binocular depth cues
relying on both eyes viewing an image
stereopsis
refers to the 3d image of the world resulting from binocular vision
retinal convergence
depth cue that results from the fact that your eyes must turn inward slightly to focus on near objects
binocular disparity
results from the fact that the closer an object is, the less similar the info arriving at each eye will be
visual cliff
Eleanor Gibson and Richard walk developed it. Involved glass tabletop that infants were scared to cross which implies that depth perception is partially innate
Gestalt approach
based on top down theory, emphasizes that the whole of anything is greater than its parts
top down theory
most perceptual stimuli can be broken down into figure ground relationships
proximity
the tendency to see objects near each other as forming groups
similarity
the tendency to prefer grouping like objects together
symmetry
the tendency to perceive forms that make up mirror images
continuity
the tendency to perceive fluid or continuous forms, rather than jagged or irregular ones
closure
the tendency to see closed objects rather than those that are incomplete
law of pragnanz
we tend to see objects in their simplest forms
feature detector approach
a process by which the nervous system sorts or filters complex natural stimuli in order to extract behaviorally relevant cues that have a high probability of being associated with important objects or organisms in their environment, as opposed to irrelevant background or noise
constancy
we know that a stimulus remains the same size, shape, brightness, weight or volume even though it does not appear to be
motion detection
process through which humans and other animals orient themselves to their own or others’ physical movements
apparent motion
an illusion of motion or change in size of a visual stimulus
phi phenomenon
optical illusion in which stationary objects shown in rapid succession, transcending the threshold at which they can be perceived separately, appear to move
stroboscopic effect
a perceptual phenomenon in which an appearance of motion or lack of motion occurs when the stimulus is not viewed continuously but in distinct separate stages
autokinetic effect
visual perception in which a stationary, small point of light in an otherwise dark or featureless environment appears to move
