Perception Flashcards
Perception is more than just _____
sensation
Perception is a function of ________ and ___________ processes
Top down and bottom up
What is moon illusion?
The moon is bigger on the horizon than on the sky
How did aristotle explain the moon illusion?
Atmospheric distortion
Atmospheric refraction explanation of the moon illusion
- Similar to when looking at an object under water that appears bigger than really is
- not supported
- may expalin shape distortions seen for setting sun and moon
Size-distance invariance explanation of the moon illusion
Horizontal moons provides distance cues that suggest moon is far away and therefore the brain perceives it as bigger (constructivist)
Emmert’s Law
Size of retinal image projected by object changes in size as a linear function of distance object is away from eyes
Retinal image gets smaller as the object gets _____
Farther
What supports size-constancy?
After-images; they appear larger on farther surfaces but smaller on closer surfaces although the retinal image size did not change
What help us perceive depth or distance?
Distance cues
Color, brightness, shadow/shading, texture are all _____
Distance cues
Motion parallax, accomodation, linear perspective, occlusion/interposition, aerial perspective, and relative height are all ______
distance cues
Size distance paradox question about moon illusion
How can the horizon moon appear larger because it is further away (size distance invariance) and yet at the same time it also appears nearer?
Apparent distance explanation for the size distance paradox
It is a 2 step process to perceive moon:
1- bottom up: unconscious registration of distance information like terrain means further away
2-Distance judged on cognitive knowledge (larger objects are closer)- top-down
When looking at two objects of equal size but at different distances, the activity in the V1 matches __________ size. (what method did they use) What did these results reflect?
- Perceived; fMRI
- recurrent (feedforward & feedback) processing of distance perception that then affects size perception
If you change the distance of the background after you show participants after images, the V1 activity will change as a function of _______ of background. Is that the same as actual or perceived size?
Distance; perceived size
If you use TMS over primary visual cortex at various times and test whether people can identify if object is a mammal or bird, what are testing? what are the results?
You are testing feedforward-feedback hypothesis? TMS dirupted performance aka feedforward or feedback activity were both disrupted
Why do we see details of moon surface on horizon?
Visual acuity can be improved with illusion that is perceived to be larger or easier to see.
Muller Lyer Illusion
Slide 29
You look at two equal length lines but one seems to be longer because of Vs at the ends
Why do people who live in dense jungle environments experience weaker illusions?
Because they do not see more 2D lines as part of the 3D world we know of; i.e. lines defining a house
Top-down explanations of illusions
These illusions work because of our knowledge of the world and our familiarity with the size of objects
Name three perceptual features of the moon
- Shape=circular
- Color=white
- Texture=random
Name some perceptual knowledge of the moon
Celestial object, sphere, very large inanimate object, located a long distance away, located in the sky usually at night, solid mass, cratered, lit by sun, view-invariant object
Two forms of visual agnosia
Appercpetive agnosia and associative agnosia
