Sensory Perception Flashcards
depth
allows us to figure out how far or close objects are
binocular vision (2 eyes)
give us retinal disparity
2 eyes, 2.5 in apart, allows us to get different views of objects in the world
convergence
when looking at objects far away, muscles in eyes are relaxed
close- eyes turn towards object
brain can look at how far eyes are turned–> depth
monocular cues (can be seen with 1 eye) (4)
- relative size- idea of form of object (bigger object seems closer if you know they should be same size ex. ants)
- interposition- see object in from of another object–> means it is closer
- relative height- object perceived to be higher seem farther away than those that are lower
- shading and contour- can use light and shadows to understand form of an object
motion
when we perceive an object- categorize if it is moving or not
motion parallax
relative motion
ex. in car driving, things closer appear to move fast that those far away
constancy (3)
- size constancy- casting a bigger retinal image–> in a picture, closer person appears bigger, but we know people are fairly the same size
- shape constancy- perception of shapes remain the same even if casting a different image on retina ex. door opens- shape changes
- color constancy- light seems to change color (shadows), but we know it is the same color
sensory adaptation
change in the sensitivity of your perception of a sensation
Hearing (sensory adaptation)
inner ear muscle that contracts when there are loud noises–> dampens vibrations that go into ear, protects from damage
takes some time to contract, so gunshot near ear can cause damage
touch (sensory adaptation)
sensory nerves (to temp) stop firing as much, will get desinsitized
smell (sensory adaptation)
can detect low concentrations of chemicals in the air, but over time sensory receptors become desensitized to molecules
proprioception (sensory adaptation)
sense of self, knowing where you are in space
ex. put goggles on that skew everything, and perception of world is changed. Over time brain accommodates–> image flips back
sight (sensory adaptation)
downregulation and upregulation
- lots of bright light entering eye–> pupils will constrict to protect retina, allows less light to enter back of eye–> downregulation in sensitivity
- change in sensitivity to rods and cones ex. in dark room, pupils will expand, rods and cones start synthesizing light sensitive molecules–> upregulation in sensitivity
just noticeable difference (JND) & Weber’s law
threshold that you can notice a small change (dumbell weight change, whispering in quiet room)
I (intensity of stimulus), delta I= JND
Weber’s law- ratio of the increment threshold to the background intensity is constant
(delta I)/I = K –> weber fraction, linear relationship
absolute threshold of sensation
minimum intensity of a stimulus that is needed to detect a stimulus at any time
50% of the time
individual differences- some can detect while other cannot
Intensity vs. % correct detections
higher intensity–> more likely to detect
influenced by many factors (text examples)
1. expectations
2. experiences
3. motivation
4. alertness (vs. drowsiness)
subliminal- stimuli that is below absolute threshold of sensation
difference threshold
not the same as absolute threshold
smallest difference in stimulation that can be detected 50% of the time
ex. light that gradually increases intensity- DT is when you notice it is brighter
somatosensation
information about sensations (ex. walking down street)
- types- temperature (thermoception), pressure (mechanoception), pain (nociception), position (proprioception)
- intensity- how quickly neurons fire
- timing-firing- nonadapting neuron, slow-adapting neuron (more at start), fast-adapting neuron (start and stop)
- location- demitomes
vestibular system
balance and spacial orientation
receptors in our inner ear–> cochlea
1. each semi-circular canal lines up with x, y, z axis
each canal filled with fluid–> endolymph
when we rotate along certain plane–> causes endolymph to shift within that canal–> allows us to sense what plane we are in (and strength)
2. otolithic organs- include utricle and saccule- detect linear acceleration and positioning, use gravity
crystals that move when we move, and pull on hair cells–> triggers AP –> info to brain
dizziness–> continued movement of endolymph even when still results in signals to brain
**signal detection theory (come back- confusing)
decision making w/ uncertainty
at what point is a signal strong enough to notice it
signal present and yes–> hit
present and no–> miss
absent and yes–> false alarm
absent and no–> correct rejection
d’= strength of a signal, c= strategy
conservative ( say no unless 100% sure signal is present)–> may get some misses
liberal strategy (always say yes)–> will get hits, but also some false alarms
attention processing (2)
- bottom up stimulus influences perception, no preconceived idea of what you are looking at
data driven - top down- uses background knowledge to influence perception
ex. where’s waldo- bottom up- not goal driven, top down- looking for waldo
Gestalt principles (6)
laws to explain how we perceive things the way we do
- similarity- items that are similar to one another are grouped together by our brains
- pragnanz- reality is reduced to simplest form (see shapes)
- proximity- objects that are close to one another are grouped together
- continuity- lines are seen as following the smoothest path
- closure- objects grouped together are seen as a whole (ignore gaps and see contour lines)
