unit 3 - sensation & perception Flashcards
sensation
to represent the world, we must detect physical energy (stimulus) from the environment and convert into neural signals
perception
when we select, organize, interpret, our sensations
transduction
physical energy and converting it into neural signals
bottom up processing
analysis of the stimulus begins with the sense receptors and works our way up in our brain and mind.
ex: stubbing your toe on a chair
top down processing
info processing guided by higher level mental processes as we construct perceptions drawing on our experiences and expectations
ex: y_u c_n r_ad my mi_d
absolute threshold
minimum stimulation needed to detect a particular stimulus 50% of the time
ex: hard to hear whispers but easy to hear normal voice
difference threshold
minimum difference between 2 stimulus required for detection 50% of the time called just noticeable difference (JND)
ex: you change the volume of the car by one level and someone complains too loud.
weber’s law
states that the amount of stimulus needed to notice a change doesn’t depend on the amount or strength of the stimulus change, but that it depends on how proportionate the change is from the strength of the original stimulus
ex: a person is much more likely to react to a quiet commercial that suddenly doubles in volume than a commercial that only slightly increases in volume
subliminal threshold
stimuli below one’s absolute threshold for consciousness awareness
can’t be seen by the naked eye or consciously heard
ex: visual stimuli that is flashed so quickly on a screen that a person can’t process it so therefore they are unaware they have seen anything
signal detection theory
a theory predicting how and when we detect the presence of a faint stimulus (“signal”) amid background stimulation (“noise”)
Basically, we notice things based on how strong they are and on how much we’re paying attention
influences of signal detection theory
experience
expectation
motivation
fatigue
sensory adaptation
diminished sensitivity and consequence of constant stimulation
ex: wearing glasses or jewelry
figure ground principle
we naturally organize what we see into objects (figures) that stand out from their background (black & white backgrounds)
closure principle
we fill in the gaps to create a complete whole object
proximity principle
we group nearby figures together
ex: players sitting together on a bench as one team
similarity principle
we group similar figures together
ex: triangles vs circles
connectedness principle
we perceive items that are uniform and linked as a single unit
continuity principle
we are more likely to see continuous and smooth flowing lines rather than broken or jagged ones.
This is because once our eyes begin to follow something, they will continue to travel in that direction until it encounters another item or object
depth perception is our ability to
perceive object in 3 dimensions and to judge distances
- even infants and newborn animals show this as seen by visual cliff
- we use both monocular + binocular cues to perceive depth
what 4 things are monocular cues
“IRL text”
I - Interposition
R - Relative Size
L - Linear Perspective
Text - Texture Gradient
what type of cue is relative height + describe it
monocular cue
- We perceive objects that are higher to be farther away from us
what type of cue is relative size + describe it
monocular cue
even if 2 images in reality are the same size, we would perceive the one closest to us to be larger
what type of cue is interposition + describe it
monocular cue
if one image covers another, it looks closer & larger
what type of cue is linear perspective + describe it
monocular cue
parallel lines look like they come together in the distance
what are binocular cues?
“BiCR” - like Bicker & Bi for 2 items
C - Convergence
R - Retinal Disparity
what type of cue is convergence and describe it
binocular cue
uses both eyes to focus on the same object. As an object moves close, the eyes come closer together to focus. As the eye look at an object further away, the eyes move further apart to focus.
what type of cue is retinal disparity and describe it
binocular cue
used to perceive depth between two near objects. It does so by comparing the different images from both retinas. Each eye receives different images because they are usually around two and half inches apart
stroboscopic movement
we perceive movement in slightly varying images shown in rapid succession
ex: stillmotion
what is phi phenomenon
an illusion of movement that arises when stationary objects—light bulbs, for example—are placed side by side and illuminated rapidly one after another. The effect is frequently used on theatre marquees to give the impression of moving lights
perceptual constancy
it refers to our tendency to see familiar objects as having consistent color, size and shape, regardless of changes in lighting, distance or angle of perspective
– > our brains interpret stimuli as they are assumed to be, rather than as they actually are
muller lyer illusion
two horizontal line segments that are perceived to have different lengths depending on whether they have arrowheads or arrowtails at their endpoints
ponzo illusion
two parallel horizontal lines of equal length appears to be longer than the bottom of the two lines when they are flanked by oblique lines that are closer together at the top than they are at the bottom (railway lines)
amex illusion
uses background info for the reference
restored vision
After cataract surgery, blind adults were able to regain sight. These individuals could differentiate figure and ground relationship however had difficulty discriminating a circle and a triangle.
sensory deprivation/perceptual isolation
suggests vision is partly an aquired sense
ex: kittens raised without exposure to horizontal lines later had difficulty perceiving horizontal bars
perceptual adaptation
visual ability to adjust to an artifically displaced visual field + humans can adapt to an upside down world
ex: drunk goggles
Perceptual set
A Mental predisposition to perceive one thing and not another. What you see in the center picture is influenced by flanking pictures. (same image = different perception)
schemas
are concepts that organize and interpret unfamiliar information, schemas develop through experience
context effects
a given stimulus can evoke radically different perceptions, based on the immediate context of the stimulus
what does extrasensory perception mean and does it exist
perception without sensory input and it doesn’t
claims of ESP
telepathy, clairvoyance, precognition, psychokinesis
order of vision
cornea, pupil, iris, lens, vitreous humor, retina, optic nerve (CPRO)
hue
dimension of color determined by wavelength
wavelength
distance from peak of one wave to peak of next
short wave length means what
high frequency + blue colors
long wave lengths mean
low frequency + red color
intensity/brightness
amt of energy determined by amp
short amp : low brightness/dim
long amp: high/bright
nearsightedness
nearby objects are seen more clearly than distances (elongated eye + image focuses before it hits retina)
farsightedness
faraway objects are seen more clearly than near (eye shortened + image focuses after it hits retina)
pupil
just a space that can expand or contract
iris
colored part of eye, controls amount of light passing through
cornea
clear, dome shaped surface that covers front of eye
lens
expands and contracts with ciliary muscles + focuses light rays onto the retina
vitreous humor
clear jelly-like substance that fills center of the eye. It helps to keep the eye round in shape
retina
light-sensitive nerve layer that lines the back of the eye. Here the image is inverted
transduction
transformation from energy stimulus to neural impulse
fovea
point of central focus
order of things in retina
- photoreceptors
- bipolar cells
- ganglion cells
- optic nerve
- back to front wall
photoreceptors difference between cones + rods
cones:
color (RBG)
functions well in light/daytime
center (fovea)
detects detail
each cone has a bipolar cell
rods:
black white + grey
needed for twilight + peripheral vision
low ability to detect detail
why do we have a blind spot
the optic nerve passes through the retina, where there are no photoreceptor cells there to detect light
why don’t we get tripped up by our blindspot more often?
your other eye makes up for it : each eye sends data to your brain on its own, so your brain fills in what’s missing
feature detectors
the ability to detect certain types of stimuli, like movements, shape, and angles, requires specialized cells in the brain called feature detectors. Without these, it would be difficult, if not impossible, to detect a round object, like a baseball, hurdling toward you at 90 miles per hour.
parallel processing
our ability to deal with multiple stimuli simultaneously
- brain divides what it sees into 4 parts (color, motion, shape, depth)
young-helmholtz (trichromatic) theory
based on behavioral experiments, Helmholtz suggested that retina contains 3 receptors sensitive to red, blue, green colors (RBG) and that RBG combine to create all colors
color blindness
an inability to see the difference between certain colors (weakness in cones)
causes: genetic defect by disease of optic nerve of retina + mostly in males
can’t be fixed
opponent-process theory
suggests there are opposing color receptors in the brain: red-green, blue-yellow, and black-white
afterimages
a type of optical illusion in which an image continues to appear briefly even after exposure to the actual image has ended; neg after image sensation of opposing colors after viewing
color constancy
ability to perceive colors as relatively constant even with different light sources
how does sound travel through the ear
ear canal, eardrum, middle ear, cochlea
frequency (pitch)
short wave = high pitch
long wave = low pitch
intensity (loudness)
great amp = loud sounds
small amp = soft sounds
transduction in ear
hair cells in cochlea vibrate with sound waves + translates them into a neural message
frequency theory
rate of nerve impulses traveling up the auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch
- hearing sound stimuli at low frequencies -
place theory
suggests that sound frequency stimulate basilar membrane at specific places resulting in perceived pitch
- high frequencies -
localization of sound
bc we have 2 ears, sounds that reach one ear faster than the other makes us localize sound
noise induced hearing loss
damage to hair cells overtime:
any sound loud enough to produce tinnitus (ear ringing) causes some damage, small amts of damage accumulate overtime
high intensity (loud) sounds tear off hair cells of inner ear
ear ringing = damage to hair cells
conduction deafness
hearing loss caused by damage to the mechanical system that conducts sound waves to cochlea
- may be corrected with surgery or hearing aids
sensorineural deafness
hearing loss caused by the cochlea’s receptor cells or to the auditory nerve, also called nerve deafness
- permanent condition
cochlear implant
small complex e-device that helps provide a sense of sound to profoundly deaf person or just people with severely hard hearing
- doesn’t restore normal hearing
what are the 4 senses of skin
pressure, warmth, cold, and pain
** only pressure has identifiable receptors, all other skin sensations are variations of pressures
pain
tells our body that something is wrong
gate control theory
Melzak & Wall (1965 + 1983) proposed that our spinal cord contains neurological gates that either block pain or allow it to be sensed
what is substance P
neurotransmitter involved in the transmission of pain messages…tells the gate to open and send the message to the brain
where is pain sent in brain
somatosensory cortex (sensory parts of pain - judgement, location & intensity)
areas of limbic system (emotional + motivational components of pain)
prefrontal cortex (suffering & worrying about future)
phantom limb pain
people who are missing a limb feel painful sensations that seem to be originating from the missing part
- might be due to cross wiring in somatosensory cortex with nearby areas taking over for missing lib
what type of sense is gustation
somatic bc it is on the skin (surface of the tongue)
taste sensations
sweet, sour, salt, bitter, umami (savory), astringent (chem/acidic)
what are chemical senses
taste and smell bc particles of stimuli enter body in order to sense it
why is smell associated with memories
bc the brain region for smell is closely connected with the limbic system involved with memory
what is sensory interaction
when one sense affects another sense
ex: closing nose means you can feel texture of food but not taste
kinesthesis
sense of our individual body parts’ position and movement
ex: touching nose without looking
vestibular sense
monitors the head and the body’s whole position … located in ear
ex: spinning in chair makes you dizzy
