unit 3 - active learning

Question 1

what is the guiding principle of gestalt?

Answer 1

this theory of perceptual organization is founded on the idea that “the whole is greater than the sum of its parts”

Question 2

what is pragnaz? what do we do perceptually?

Answer 2

pragnaz is a guiding principle of gestalt, directly translating to “good figure”. it is otherwise known as the law of simplicity; we tend to simplify things as possible

Question 3

in the gestalt theories, what are the different ways our brains answer “what should I be focusing (what should I group) on?” PSCCC

Answer 3

Proximity –> how close are things?
Similarity –> what objects look alike?
Continuity –> where does a pattern continue?
Connectedness –> are things ordered as a unit?
Closure –> how can I fill gaps?

Question 4

what dimensions are used to percieve depth/distance?

Answer 4

we use length, width, and depth (also height)

Question 5

what are the binocular cues for depth perception? CR

Answer 5

convergence: a neuromuscular cue that, as an object is near, our eyes look inward and as it is farther, our eyes look straightforward

retinal disparity: images from L and R eye differ, and when that difference is greater, the object is closer and when it lower, the object is farther

Question 6

what are the monocular cues for depth perception? RILHTL

Answer 6

relative size: images that are larger are perceived as closer

interposition: images look further if they are blocked or behind other objects and closer if they are isolated

light + shadow: haze and shade are perceived as further; brightness is associated with proximity

height: the top of our visual fields are perceived as further away
texture: the more detailed an object, the closer it is, the further, the less detailed
linear: parallel lines when objects diverge are seen as further apart.

Question 7

how do we EXPERIENCE (not perceive) sensation?

Answer 7

sensory transduction occurs, where an outside stimuli –> sensors –> sensations (electrical)

transduction requires the stimulation of neurons BUT this must occur when the stimuli reaches absolute threshold (50%)

Question 8

how do our absolute thresholds allow for sensory adaptation?

Answer 8

while absolute thresholds are the intensity of the stimuli required to be sensed 50% of the time, sensory adaptation is the decline in sensitivity to certain stimuli experienced after constant exposure; meaning our absolute thresholds increase over time as we grow accustomed

Question 9

how does the difference threshold relate to Weber’s law?

Answer 9

the difference threshold is the minimum change in the intensity of stimuli required for detection, hence it is labeled the “just-noticeable” threshold. Weber’s law just puts this into a mathematical form, positing that the dt occurs at a ratio of change v.s. perceived change.

Question 10

what is the matrix associated with the signal detection theory?

Answer 10

was there a signal? true = hit; false = miss
was there not a signal? yes = fake; no = correct rejection
- this is the minimum stimulus needed for awareness

Question 11

how do our expectations influence our sensations?

Answer 11

top-down processing: when we walk into scenarios with built schemas, cultural or contextual influences, we perceive and process the experience before actually sensing it, leaving to altered experiences

this is related to perceptual set, or the tendency to perceive some parts of sensory data while ignoring others

Question 12

how does motivation or emotion affect what we see?

Answer 12

this is an extension of top-down processing: hungry people see food in ambiguous pictures (perceptual set), angry people see hostility in normal behaviors, etc.

Question 13

what are schemas and what are they built by?

Answer 13

schemas are the mental frameworks we have for organizing our understanding of the world around us, and it is built since birth, encapsulating our daily lives, perceptions of good and bad, etc.

Question 14

who were the psychologists behind gestalt theories?

Answer 14

Wertheimer, Kohler, Koffka, Paris

Question 15

how is light transducted into vision?

Answer 15

at the retina…light stimulates the back of the eye (rods=b/w, cones=rbg). then, BIPOLAR CELLS with one dendrite and one axon send a unidirectional in/out signal to the ganglion to the neural pathway via optic nerve

Signals from the optic nerve travel to the occipital lobe, in the primary visual cortex responsible for processing light, color, line, slope, angle, and motion (credits Hubel and Wiesel)

Question 16

how is light perceived and sensed?

Answer 16

light has two properties: wavelength and amplitude. wavelength is the distance between peaks and determines hue (400-650 nm) while amplitude, determining intensity

*greatest acuity? most concentrated cones/rods

Question 17

what is the two-stage theory of color vision?

Answer 17

first = trichromatic theory (credits Young and Helmholtz): photoreceptors (cones) work in teams of three to sense RBG and combinations of signal fires determine color

second = opponent-process theory: as info transfers from cones to ganglion cells, some neurons excite others while some are inhibited/opposed. fatigue, then explains after images because the overexcited photoreceptors shut off while the previously inhibited color photoreceptors turn on, providing a direct contrast (think red to green, blue to orange, etc.)

Question 18

what is colorblindness the result of?

Answer 18

malfunctioning or absent photoreceptors; cb people cannot distinguish between excitatory and inhibitory signals OR lack responsive cones.

mono = b/w
di = r/g; y/b
tri = normal

Question 19

what are the three types of illusions, and how do they function?

Answer 19

physical: scale is distorted to manipulate our MONOCULAR CUES for depth perception
physiological: overstimulation causes fatigue of photoreceptors or feature detectors
cognitive: mismatch of expectation, perception, and sense, top-down processing, perceptual set, context, gestalt
* MOST ILLUSIONS ARE COMBINATIONS OF THE TYPES OF ILLUSIONS

Question 20

what are the characteristics of sound?

Answer 20

frequency/pitch and amplitude/loudness.

Question 21

what is the process of and conditions for audition?

Answer 21

conditions are: sound source, medium, reciever

i. outer ear via air and sound –> pinna + tympanic membrane gather and concentrate sound waves
ii. middle ear via bone medium –> stapes, stirrups, ossicles vibrate
iii. inner ear via liquid medium –> cochlea and cillia conduct sound to auditory nerve to allow for transduction

Question 22

what are the causes/changes associated with the two types of hearing loss?

Answer 22

sensorineural hearing loss affects loudness, clarity, and range; cochlear cilia and auditory nerve = no transduction. usually in BOTH ears; aging, disease, trauma

conductive hearing loss occurs when sound cannot properly propagate through outer/middle ear. occurs in one or both ears, due to ear wax, trauma, bone damage, wear, blockage

Question 23

How does gustation and olfaction occur?

Answer 23

tasting and smelling require that a compound is dissolved or evaporated to activate receptors.

taste: bitter, salty, sweet, sour, umami. our tastebuds contain hundreds of taste receptors

Question 24

do our senses interact? what are some examples?

Answer 24

sensory interactions occur all of the time to complete and inform our sensations and perceptions

touch (pressure, temp), pain, vestibular sense (balance, movement), kinesthetic (position of joints)
I. pet a cat = temp and pressure due to resistance
II. pain hypersensitivity results in reliance on other senses for survival
III. kinesthesia occurs when descending stairs in the dark (lack of sight compensated by vestibular sense)