Sensory Perception

Question 1

Visual cues allow us to perceptually organize
by taking into account what cues?

Answer 1

depth, form, motion, constancy

Question 2

Humans have two eyes which allow them to receive visual cues from their environmentby binocular cues. These give them a sense of ?

Answer 2

depth, gives retinal disparity

Question 3

what is a retinal disparity

Answer 3

Eyes are ~2.5 inches apart which allows
humans to get slightly different views of objects of the world around. Gives humans an idea on depth.

Question 4

What is Convergence? when things are far apart when things are close?

Answer 4

Gives humans an idea of depth as well based on how many eyeballs are turned. Gives humans a sense of depth.
§ Things far away – muscles of eyes relaxed.
§ Things close to us – muscles of eyes contract.

Question 5

Humans also have visual cues they receive which they do not need two eyes for. These are called?

Answer 5

monocular cues

Question 6

what are monocular cues?

Answer 6

Relative size- Can infer with one eye. The closer an object it is perceived as being bigger. Gives us an idea of form.

Interposition (overlap)- Perception that one object is in front of another. An object that is in the front is closer.

Relative height- things higher are perceived to be farther away than those that are lower.

Shading and contour- using light and shadows to perceive form depth/contours – crater/mountain.

Motion parallax- “relative motion” Things farther away move slower,
closer moves faster.

Question 7

Sensory adaptation: hearing

Answer 7

inner ear muscle: higher noise = muscle contract (this dampens vibrations in inner ear, protects ear drum.) Takes a few seconds to kick in! So does not work for immediate noises like a gun shot, but it works for being at a rock concert for an entire afternoon

Question 8

Sensory adaptation: Touch

Answer 8

temperature receptors desensitized over time.

Question 9

Sensory adaptation: Smell

Answer 9

desensitized receptors in your nose to molecule sensory information
over time.

Question 10

Sensory adaptation: Proprioception

Answer 10

is the sense of the position of the body in space i.e. “sense of
balance/where you are in space.”

Experiment: goggles that make everything upside down and the
perception of the world, and eventually you would accommodate over
time, and flip it back over.

Question 11

Sensory adaptation: Sight

Answer 11

down regulation or up regulation to light intensity.

§ Downregulation: light adaptation. When it is bright out, pupils constrict (less light enters back of eye), and the desensitization of rods and cones become desensitized to light)

§ Up regulation: dark regulation. Pupils dilate-, rods and cones start synthesizing light sensitive molecules

Question 12

just noticeable difference (JND)

Answer 12

The threshold at which you’re able to notice a change in any sensation

Question 13

Weber’s Law formula

Answer 13

ΔI (JND)/I (initial intensity) = k (constant)

Question 14

Absolute threshold of sensation

Answer 14

The minimum intensity of stimulus needed to detect a particular stimulus 50% of the time.

Question 15

Absolute threshold can be influenced by a # of factors

Answer 15

o Expectations – ex. Are you expecting a text.
o Experience (how familiar you are with it) – ex. Are you familiar of the phones
text vibration sound.
o Motivation – ex. Are you interested in the response of the text
o Alertness – Are you awake our drowsy. Ex. You will notice text if you are awake

Question 16

Subliminal stimuli

Answer 16

stimuli below the absolute threshold of sensation.

Question 17

thermoception

Answer 17

Temperature

Question 18

Mechanoception

Answer 18

pressure

Question 19

Nociception

Answer 19

pain

Question 20

The intensity in regards to neurons?

Answer 20

how quickly neurons fire for us to notice. Slow = low intensity, fast = high intensity.

Question 21

Neurons encode for timing in 3 ways:

Answer 21

o Non-adapting- neuron consistency fires at a constant rate

o Slow-adapting - neuron fires in the beginning of the stimulus and calms down after a
while

o Fast-adapting - neuron fires as soon as stimulus start…then stops firing. Starts
again when stim stops).

Question 22

The Vestibular System sensation:

Answer 22

Balance and spatial orientation

Question 23

The Vestibular System comes from

Answer 23

Comes from both inner ear and limbs.

Question 24

Semicircular canals role?

Answer 24

Canal is filled with endolymph, and when we rotate the fluid shifts in the semicircular
canals – allows us to detect what direction our head is moving in, and because we can
detect how quickly the endolymph is moving we can determine the strength of rotation.

Question 25

Otolitchic organ role

Answer 25

Otolithic organs (utricle and saccule) help us to detect linear acceleration and head positioning.

In these are CaCO3 (Calcium carbonate) crystals attached to hair cells in a viscous gel.

If we go from lying down to standing up, they move and pull on hair cells, which triggers AP. These would not work very well w/o gravity! Buoyancy can have effects as well, particularly without visual cues on which way is up/down.

Question 26

why do we feel dizzy?

Answer 26

Endolymph doesn’t stop spinning the same time as we do, so it continues moving and indicates to brain we’re still moving even when we’ve stopped – results in feeling of dizzines

Question 27

Signal Detection Theory:

Answer 27

Looks at how we make decision under conditions of uncertainty – discerning between important stimuli and unimportant “noise”

Question 28

Options in signal detection: hit/miss/false alarm/correct rejection

Answer 28

§ Hit, the subject responded affirmative when a signal was present,
§ False Alarm, the subject perceived a signal when there was none
present;
§ Correct Rejection, a correct negative answer for no signal
§ Miss, a negative response to a present signal

Question 29

Strength of a signal is variable d’
d’: Strength

Answer 29

§ hit > miss (when there is a strong signal),
§ miss > hit (weak signal)

Question 30

strength of a signal is variable c is a strategy

Answer 30

2 strategies
* Conservative strategy - always say no unless 100% sure signal is
present. Bad thing is might get some misses.
* liberal strategy- always say yes, even if get false alarms.

Question 31

Bottom up Processing

Answer 31

Begins with stimulus. Stimulus influences what we perceive (our perception).
o No preconceived cognitive constructs of the stimulus (never seen it before)
o Data-driven. And the stimulus directs cognitive awareness of what you’re looking
at (object)
o Inductive Reasoning. Always correct.

Question 32

Top-down Processing:

Answer 32

uses background knowledge influences perception. Ex. Where’s waldo
o Theory driven. Perception influenced by our expectation
o Deductive Reasoning
o ex. creating a cube when it’s not there! Not always correct.

Question 33

Gestalt Principles similarity

Answer 33

items similar to one another grouped together by brain. Ex: The brain automatically organizes these squares and circles in columns, and not in rows.

Question 34

Gestalt Principles Pragnanz:

Answer 34

reality organized reduced to simplest form possible. Ex. Olympic rings, where the brain automatically organizes these into 5 circles, instead of more complex shapes.

Question 35

Gestalt Principles Proximity:

Answer 35

objects that are close are grouped together, we naturally group the closer things together rather than things that are farther apart. Ex: We group things close to one another together.

Question 36

Gestalt Principles Continuity:

Answer 36

lines are seen as following the smoothest path. Ex: You group the line together!

Question 37

Gestalt Principles Closure:

Answer 37

objects grouped together are seen as a whole. Mind fills in missing information. Ex. You fill in the triangle even though there is none.

Question 38

Gestalt Principles Symmetry

Answer 38

the mind perceives objects as being symmetrical and forming around a center point.

Question 39

Gestalt Principles Law of Common Fate:

Answer 39

For example, if there are an array of dots and half the dots are moving upward while the other half are moving downward, we would perceive the upward moving dots and the downward moving dots as two distinct units.

Question 40

Gestalt Principles Law of Past Experiences:

Answer 40

The law of past experience implies that under some circumstances visual stimuli are categorized according to past experience. If two objects tend to be observed within close proximity, or small temporal intervals, the objects are more likely to be perceived together.

For example, the English language contains 26 letters that are grouped to form words using a set of rules. If an individual reads an English word they have never seen, they use the law of past experience to interpret the letters “L” and “I” as two letters beside each other, rather than using the law of closure to combine the letters and interpret the object as an uppercase U

Question 41

Contextual Effects:

Answer 41

the context in which stimuli are presented and the processes of perceptual organization contribute to how people perceive those stimuli (and also that the context can establish the way in which stimuli are organized)