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
