Cognitive Psychology Chapter III Perception (81-90)

Question 1

List informational media for all 5 senses:

Answer 1

• reflected light (electromagnetic waves)
• sound waves
• released molecules (olfaction)
• released molecules (gustation)
• mechanical pressure and vibration (touch)

Question 2

If the tree falls in the forest and no one is around to hear it, does it make a sound?

Answer 2

Yes, although no perceived sound. However, there is a distal object and an informational medium.

Question 3

How should we think about the line between perception and cognition?

Answer 3

We should view these processes as part of a continuum.

Question 4

How should we think about the line between sensation and perception?

Answer 4

We should view these processes as part of a continuum.

Question 5

What are stabilized images?

Answer 5

Images that do not move across the retina because they actually follow the eye movements.

Question 6

What has been shown with stabilized images? (Ditchburn 1980)

Answer 6

The use of this technique has shown that constant stimulation of the cells of the retina gives the impression that the image disappears.

Question 7

What is the name of the phenomenon in which receptor cells adapt to constant stimulation by seizing to fire until there is a change in stimulation?

Answer 7

Sensory adaptation

Question 8

Why do changing sensations seem necessary for perception?

Answer 8

Given the nature of our sensory receptors constant stimulation causes sensory adaptation.

Question 9

Give an example for perceptional constancy!

Answer 9

Approaching a person, the amount of space on your retina devoted to images of this person becomes increasingly larger. On the one hand this proximal sensory evidence suggests that the person is becoming larger. on the other hand, you perceive that the person has remained the same size.

Question 10

Define perceptual constancy!

Answer 10

Perceptual constancy occurs when our perception of an object remains the same even when our proximal sensation of the distal object changes (Gillam, 2000).

Question 11

Name two of the several kinds of perceptional constancies!

Answer 11

Size and shape constancies

Question 12

Define size constancy!

Answer 12

Size constancy is the perception that an object maintains the same size despite changes in the size of the proximal stimulus.

Question 13

Name two illusions that draw on size constancy!

Describe a third!

Answer 13

Ponzo Illusion
Müller-Lyer Illusion
———————
Two circles of same size surrounded by circles of different sizes. Size-relation between inner and outer circles affects perception.

Question 14

Describe what happens in the Ponzo illusion!

Answer 14

Converging lines mimick a depth cue, so that two horizontal objects/lines appear to be of different length although they are not.

Question 15

Describe what happens in the Müller-Lyer illusion!

Answer 15

Two lines of equal length appear to be of different length.

Question 16

Name one possible explanation for the Müller_lyer illusion! (remember: we are not certain, why it actually occurs!)

Answer 16

• The diagonal lines at the endings might be implicit depth cues (Coren, Girgus, 1978)

Question 17

Give an illustrative example for shape consistency!

Answer 17

Pictures of an opening door. The door-picture’s actual shape changes, yet is perceived as consistent.

Question 18

Parts of the brain involved in shape analysis could be localized in the …

Answer 18

… extrastriate cortex (Kanwisher et al., 1996, 1997).

Question 19

What are we using depth perception for?

Answer 19

• assessing distances

Question 20

Why is 3D perception puzzeling at first?

Answer 20

The proximal stimuli on our retinas comprise only 2D projections of what we see.

Question 21

Why are pictures such as the impossible staircase or M. C. Escher’s “Waterfall” so confusing?

Answer 21

Because they provide contradictory depth cues.

Question 22

What 5 monocular depth cues did Carlo Crivelli use in “The Annunciation”?

Answer 22

• texture gradients (larger grains, further apart)
• relative size (tiles of same yet different size)
• interposition (sth. in the front blocks the view)
• linear perspective (lines/walls seem to converge)
• location in the picture plane (rear -> higher)

Question 23

What 2 monocular depth cues are not depicted in Crivelli’s picture?

Answer 23

• Aerial perspective

- Motion parallax

Question 24

Texture gradients:

Answer 24

Closer: larger grains, farther apart

Farther away: smaller grains, closer together

Question 25

Relative size:

Answer 25

Closer: bigger

Farther away: smaller

Question 26

Interposition:

Answer 26

Closer: partially obscures other object

Farther away: is partially obscured by other object

Question 27

Linear perspective:

Answer 27

Closer: Apparently parallel lines seem to diverge estate move away from the horizon
Farther away: apparently parallel lines seem to converge as they approach the horizon

Question 28

Aerial perspective:

Answer 28

Closer: images seem crisper, more clearly delineated

Farther away: images seem fuzzier, less clearly delineated

Question 29

Location in the picture plane:

Answer 29

Closer: above the horizon, objects are higher in the Picture plane. below the horizon, objects are lower in the Picture plane
Farther away: above the horizon, objects are lower in the picture plane. below the horizon, objects are hired in the picture plane

Question 30

Motion parallax:

Answer 30

Closer: objects approaching get larger than ever increasing speed (Big and moving quickly closer)
Farther away: objects departing get smaller at an ever decreasing speed (small and moving slowly farther away)

Question 31

Distance is also effected by imagined effort to get to a specific location, for example when…

Answer 31

… wearing a heavy backpack (Proffitt et al., 2003, 2006).

Question 32

Give an example of expertise’s influence on perception!

Answer 32

Well playing tennis players report that the tennis ball looks relatively large (Wilt and Proffitt, 2005).

Question 33

In cases where expertise influences perception:

Answer 33

Perceptions are in part a function of the quality of performance (Wilt and Proffitt, 2005).