Cognitive Psychology Chapter III Perception (81-90) Flashcards
List informational media for all 5 senses:
- reflected light (electromagnetic waves)
- sound waves
- released molecules (olfaction)
- released molecules (gustation)
- mechanical pressure and vibration (touch)
If the tree falls in the forest and no one is around to hear it, does it make a sound?
Yes, although no perceived sound. However, there is a distal object and an informational medium.
How should we think about the line between perception and cognition?
We should view these processes as part of a continuum.
How should we think about the line between sensation and perception?
We should view these processes as part of a continuum.
What are stabilized images?
Images that do not move across the retina because they actually follow the eye movements.
What has been shown with stabilized images? (Ditchburn 1980)
The use of this technique has shown that constant stimulation of the cells of the retina gives the impression that the image disappears.
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?
Sensory adaptation
Why do changing sensations seem necessary for perception?
Given the nature of our sensory receptors constant stimulation causes sensory adaptation.
Give an example for perceptional constancy!
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.
Define perceptual constancy!
Perceptual constancy occurs when our perception of an object remains the same even when our proximal sensation of the distal object changes (Gillam, 2000).
Name two of the several kinds of perceptional constancies!
Size and shape constancies
Define size constancy!
Size constancy is the perception that an object maintains the same size despite changes in the size of the proximal stimulus.
Name two illusions that draw on size constancy!
Describe a third!
Ponzo Illusion
Müller-Lyer Illusion
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Two circles of same size surrounded by circles of different sizes. Size-relation between inner and outer circles affects perception.
Describe what happens in the Ponzo illusion!
Converging lines mimick a depth cue, so that two horizontal objects/lines appear to be of different length although they are not.
Describe what happens in the Müller-Lyer illusion!
Two lines of equal length appear to be of different length.
Name one possible explanation for the Müller_lyer illusion! (remember: we are not certain, why it actually occurs!)
- The diagonal lines at the endings might be implicit depth cues (Coren, Girgus, 1978)
Give an illustrative example for shape consistency!
Pictures of an opening door. The door-picture’s actual shape changes, yet is perceived as consistent.
Parts of the brain involved in shape analysis could be localized in the …
… extrastriate cortex (Kanwisher et al., 1996, 1997).
What are we using depth perception for?
- assessing distances
Why is 3D perception puzzeling at first?
The proximal stimuli on our retinas comprise only 2D projections of what we see.
Why are pictures such as the impossible staircase or M. C. Escher’s “Waterfall” so confusing?
Because they provide contradictory depth cues.
What 5 monocular depth cues did Carlo Crivelli use in “The Annunciation”?
- 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)
What 2 monocular depth cues are not depicted in Crivelli’s picture?
- Aerial perspective
- Motion parallax
Texture gradients:
Closer: larger grains, farther apart
Farther away: smaller grains, closer together
Relative size:
Closer: bigger
Farther away: smaller
Interposition:
Closer: partially obscures other object
Farther away: is partially obscured by other object
Linear perspective:
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
Aerial perspective:
Closer: images seem crisper, more clearly delineated
Farther away: images seem fuzzier, less clearly delineated
Location in the picture plane:
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
Motion parallax:
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)
Distance is also effected by imagined effort to get to a specific location, for example when…
… wearing a heavy backpack (Proffitt et al., 2003, 2006).
Give an example of expertise’s influence on perception!
Well playing tennis players report that the tennis ball looks relatively large (Wilt and Proffitt, 2005).
In cases where expertise influences perception:
Perceptions are in part a function of the quality of performance (Wilt and Proffitt, 2005).
