Lecture 15 Flashcards
visual angle
angle to an object relative to the observer’s eye
As things get closer, the visual angle ___
As things get closer, the visual angle increases
As things get farther away, the visual angle ___
As things get farther away, the visual angle decreases
“thumb” method of determining the visual angle of an object
when the thumb is at arm’s length, whatever its width covers has a visual angle of about 2 degrees. e.g. the woman’s thumb covers the width of her iPhone, so the visual angle of the iPhone, from the woman’s point of view, is 2 degrees.
Simple size-distance scaling formula
S= K ( R x D )
S= perceived size
K= a scaling constant
R= retinal size
D= perceived distance
As an object moves farther away, we perceive it to ___ __ ___ ___ because as the retinal size get smaller our perception of the distance ___
As an object moves farther away, we perceive it to remain a constant size because as the retinal size get smaller our perception of the distance increases
The Muller-Lyer illusion
straight lines with inward finds appear shorter than straight lines with outward fins, when the lines are actually the same length
An explanation for the muller-lyer illusion is ___ __-___ ___, but it does not explain everything as illusions can still be produced which don’t convey any sense of depth
An explanation for the muller-layer illusion is misapplied size-constancy scaling, but it does not explain everything as illusions can still be produced which don’t convey any sense of depth
In the muller-lyer illusion observers unconsciously perceive the fins as belonging to ___ and ___ corners. Outside corners seem ___ (appear to ‘jut out’), and thus are treated as such. Inside corners on the other hand seem ___ (appear to ‘recede’)
In the muller-lyer illusion observers unconsciously perceive the fins as belonging to outside and inside corners. Outside corners seem closer (appear to ‘jut out’), and thus are treated as such. Inside corners on the other hand seem further away (appear to ‘recede’)
If equivalently sized images are formed on the retina, and one is judged to be further away i.e. the ‘__ corner’, it will be perceived as __
If equivalently sized images are formed on the retina, and one is judged to be further away i.e. the ‘inside corner’, it will be perceived as larger
Another proposed explanation for the muller-lyer illusion is the ___ ___ theory, which states that our perception of line length depends on 2 factors:
1) The _____
2) The _____
Another proposed explanation for the muller-lyer illusion is the conflicting cues theory, which states that our perception of line length depends on 2 factors:
1) The actual length of the vertical lines
2) The overall length of the figure
Ponzo illusion
horizontal rectangular objects are placed over railroad tracks in a picture, far rectangle appears larger than the closer rectangle but both are the same size
__ ___-___ __ may offer an explanation for the ponzo illusion
Misapplied size-constancy scaling may offer an explanation for the ponzo illusion
Ames room
two people of equal size appear very different in size in the room. The room is constructed so that the shape looks like a normal room when viewed with one eye. The actual shape has the left corner twice as far away as the right corner
__-___ ___ offers a plausible explanation for the Ames room because the observer thinks the room is rectangular which would mean the women would be the same distances away (from the observer).
Woman on the right has ___ visual angle (R), the perceived distances (D) of the two women are the same, the perceived size (S) of the women on the right is ___
size-distance scaling offers a plausible explanation for the Ames room because the observer thinks the room is rectangular which would mean the women would be the same distances away (from the observer).
Woman on the right has smaller visual angle (R), the perceived distances (D) of the two women are the same, the perceived size (S) of the women on the right is smaller
Another possible explanation to the Ames room is __ ___.
Perception of size depends on size relative to other objects. One women fills the distance between the top and bottom of the room. The other woman only fills part of the distance. Thus, the woman on the right appears taller
Another possible explanation to the Ames room is relative size.
Perception of size depends on size relative to other objects. One women fills the distance between the top and bottom of the room. The other woman only fills part of the distance. Thus, the woman on the right appears taller
Moon illusion
it appears larger on the horizon than when it is higher in the sky (despite having the same visual angle). Because while the visual angle of the moon is the same, the perceived distance is different (horizon perceived as farther away than the sky), resulting in a difference in perceived size
Apparent-distance theory explaining the moon illusion
horizon moon surrounded by depth cues but moon higher in the sky has none
Animals with ___ eyes that have fields which significantly overlap afford good stereoscopic depth perception
Animals with frontal eyes that have fields which significantly overlap afford good stereoscopic depth perception
Animals with ___ eyes have poor stereoscopic depth perception (but gain a more panoramic view)
Animals with lateral eyes have poor stereoscopic depth perception (but gain a more panoramic view)
