Sensory Perception

Question 1

depth

Answer 1

allows us to figure out how far or close objects are

Question 2

binocular vision (2 eyes)

Answer 2

give us retinal disparity

2 eyes, 2.5 in apart, allows us to get different views of objects in the world

Question 3

convergence

Answer 3

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

Question 4

monocular cues (can be seen with 1 eye) (4)

Answer 4

1. relative size- idea of form of object (bigger object seems closer if you know they should be same size ex. ants)
2. interposition- see object in from of another object–> means it is closer
3. relative height- object perceived to be higher seem farther away than those that are lower
4. shading and contour- can use light and shadows to understand form of an object

Question 5

motion

Answer 5

when we perceive an object- categorize if it is moving or not

Question 6

motion parallax

Answer 6

relative motion

ex. in car driving, things closer appear to move fast that those far away

Question 7

constancy (3)

Answer 7

1. size constancy- casting a bigger retinal image–> in a picture, closer person appears bigger, but we know people are fairly the same size
2. shape constancy- perception of shapes remain the same even if casting a different image on retina ex. door opens- shape changes
3. color constancy- light seems to change color (shadows), but we know it is the same color

Question 8

sensory adaptation

Answer 8

change in the sensitivity of your perception of a sensation

Question 9

Hearing (sensory adaptation)

Answer 9

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

Question 10

touch (sensory adaptation)

Answer 10

sensory nerves (to temp) stop firing as much, will get desinsitized

Question 11

smell (sensory adaptation)

Answer 11

can detect low concentrations of chemicals in the air, but over time sensory receptors become desensitized to molecules

Question 12

proprioception (sensory adaptation)

Answer 12

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

Question 13

sight (sensory adaptation)

Answer 13

downregulation and upregulation

1. lots of bright light entering eye–> pupils will constrict to protect retina, allows less light to enter back of eye–> downregulation in sensitivity
2. 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

Question 14

just noticeable difference (JND) & Weber’s law

Answer 14

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

Question 15

absolute threshold of sensation

Answer 15

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

Question 16

difference threshold

Answer 16

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

Question 17

somatosensation

Answer 17

information about sensations (ex. walking down street)

1. types- temperature (thermoception), pressure (mechanoception), pain (nociception), position (proprioception)
2. intensity- how quickly neurons fire
3. timing-firing- nonadapting neuron, slow-adapting neuron (more at start), fast-adapting neuron (start and stop)
4. location- demitomes

Question 18

vestibular system

Answer 18

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

Question 19

**signal detection theory (come back- confusing)

Answer 19

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

Question 20

attention processing (2)

Answer 20

1. bottom up stimulus influences perception, no preconceived idea of what you are looking at
   data driven
2. top down- uses background knowledge to influence perception
   ex. where’s waldo- bottom up- not goal driven, top down- looking for waldo

Question 21

Gestalt principles (6)

Answer 21

laws to explain how we perceive things the way we do

1. similarity- items that are similar to one another are grouped together by our brains
2. pragnanz- reality is reduced to simplest form (see shapes)
3. proximity- objects that are close to one another are grouped together
4. continuity- lines are seen as following the smoothest path
5. closure- objects grouped together are seen as a whole (ignore gaps and see contour lines)