Apparent Distance Theory = ...what?

[Spreadbury]

i've finished my notes for Unit 3 Psychology and i'm focussing on revision right now, but whenever I read about the Ames Room and Apparent Distance Theory I just start thinking "wait what?"

the explanation I have for the apparent distance theory:

Apparent Distance Theory: states that when two retinal images are the same size, but one image appears to be at a greater distance, then the one that appears further away will be interpreted as larger. The perceived rectangular shape of the room is consistent with the retinal image, but not consistent with the rooms real shape. The back corners produce an equal sized retinal image because the vertical length of the further left corner is double the length (but double the distance from the observer) of the nearer right corner and the visual angle is the same for both corners. Because the observer does not have the depth cues availiable to discern the difference in distance between the corners, the equal-sized retinal images are interpreted as equal in size, producing an illusion of a rectangular room

I feel pretty sure that's wrong because it seems to be telling me about two unrelated matters and if anyone could provide me with soem corrections or a more concise definition/ explanation I would greatly appreciate it

[Visionz]

http://www.youtube.com/watch?v=Ttd0YjXF0no

My very poorly worded explanation - i understand it but im too tired to articulate it. =\
The observer has to use monocular cues which makes it difficult to judge actual depth. The shape of the room appears to be rectangular (shape constancy) despite it being very deformed. This interferes with SIZE CONSTANCY, we see two images/people appearing at the same distance yet one seems smaller. They appear smaller because in actuality they are further away however the skewed shape of the room is what gives the illusion. The shape of the room seems to maintain constancy while the size of the people is skewed.

[akira88]

Omg I know this absolutely confused the crap out of me. My psychology teacher used to be an examiner and she said that it doesn't make any sense either- the apparent distance theory DOESN'T explain the Ames Room at all. So I dunno...

[akira88]

http://www.youtube.com/watch?v=Ttd0YjXF0no

My very poorly worded explanation - i understand it but im too tired to articulate it. =\
The observer has to use monocular cues which makes it difficult to judge actual depth. The shape of the room appears to be rectangular (shape constancy) despite it being very deformed. This interferes with SIZE CONSTANCY, we see two images/people appearing at the same distance yet one seems smaller. They appear smaller because in actuality they are further away however the skewed shape of the room is what gives the illusion. The shape of the room seems to maintain constancy while the size of the people is skewed.

I know this, and it makes sense, but how does it apply to the apparent distance theory?

[Visionz]

I know this, and it makes sense, but how does it apply to the apparent distance theory?

I think I found it. Page 246 of the grivas textbook. The apparent distance theory doesnt affect the image of the people but instead the perception of the shape of the room! The back corners of the room seem to be at the same distance. The room appears to be rectangular when in fact its not. When combined with the inability to use binocular depth cues and inability to maintain size constancy we have the Ames-Room Illusion.

[bomb]

Basically, it says this....

Imagine, for example, there is a small object close to you, and it produces a certain sized retinal image.
Now, another object (which you have already percieved as being further away, produces the SAME sized retinal image.

Because the further away object creates the exact same sized retinal image as the closer one, you know that the further away one is bigger.

That, is the apparent distance theory.


Now, in relation to the Ames room...

What it's saying is, that both objects look the same distance away from the viewer. So, we judge the size depending on the size of the retinal image alone..so the person on the left will look smaller.

If they did look a different distance away from the viewer, then we would know that they are the same size

[Spreadbury]

Basically, it says this....

Imagine, for example, there is a small object close to you, and it produces a certain sized retinal image.
Now, another object (which you have already[/bi] percieved as being further away, produces the SAME sized retinal image.

Because the further away object creates the exact same sized retinal image as the closer one, you know that the further away one is bigger.

That, is the apparent distance theory.


Now, in relation to the Ames room...

What it's saying is, that both objects look the same distance away from the viewer. So, we judge the size depending on the size of the retinal image alone..so the person on the left will look smaller.

If they did look a different distance away from the viewer, then we would know that they are the same size

thanks, that makes far more sense

[vexx]

Just in case you want this definition i had from back when i did psych that i learnt for my exams/sac:

for Muller-Lyer
"The Apparent Depth or Distance Theory: The Muller-Lyer illusion involves the misapplication of size constancy. The arrowheads are seen as the outside of the building, closest to the observer; whereas the feathertails are seen as the further away corner of an inside wall. Due to the workings of size-constancy, the feathertails, that are seen as being further away, cast the same retinal image as the arrowheads so the brain ‘constructs’ or interprets it as longer and we perceive it as such. "

Ames room
"When two retinal images are the same size, but when one image appears to be at a larger distance, then the one that appears to be further away will be interpreted as larger because of the limit to monocular cues only. This demonstrates the inability to maintain size constancy over shape constancy. "

[akira88]

Ames room
"When two retinal images are the same size, but when one image appears to be at a larger distance, then the one that appears to be further away will be interpreted as larger because of the limit to monocular cues only. This demonstrates the inability to maintain size constancy over shape constancy. "

Doesn't the Apparent distance theory apply when we can use binocular cues? Not limited to monocular cues? I'm so confused

[Spreadbury]

Just in case you want this definition i had from back when i did psych that i learnt for my exams/sac:

for Muller-Lyer
"The Apparent Depth or Distance Theory: The Muller-Lyer illusion involves the misapplication of size constancy. The arrowheads are seen as the outside of the building, closest to the observer; whereas the feathertails are seen as the further away corner of an inside wall. Due to the workings of size-constancy, the feathertails, that are seen as being further away, cast the same retinal image as the arrowheads so the brain ‘constructs’ or interprets it as longer and we perceive it as such. "

for the Muller-Lyer illusion the grivas text book gives a different explanation. it explains the Muller-Lyer illusion with the Perceptual Compromise explanation... what would people say is the most straightforward/ accurate explanation for the Muller-Lyer Illusion as I got several explanation, biological factors, cognitive factors and perceptual compromise

[Visionz]

I dont know how youre meant to use the apparent distance theory. I just dont see how one of the lines appears further away or closer or whatever. Its a line ffs.. its got nothing to do with depth perception.

[vexx]

Ames room
"When two retinal images are the same size, but when one image appears to be at a larger distance, then the one that appears to be further away will be interpreted as larger because of the limit to monocular cues only. This demonstrates the inability to maintain size constancy over shape constancy. "

Doesn't the Apparent distance theory apply when we can use binocular cues? Not limited to monocular cues? I'm so confused

sorry didn't see this.. not sure what you mean? i did this all so long ago. and what i wrote above is all i remembered / what is needed to be remembered.

[Spreadbury]

ok i've tried to correct my definitions and can someone please tell me if they're accurate?

"Muller-Lyer Illusion: a visual illusion in which one of two lines of equal length, each of which has opposite shaped ends, is incorrectly perceived as being longer than the other.

Perceptual Compromise: The Muller-Lyer Illusion gives us conflicting cues. The central lines of both figures are the same, but the WHOLE figure of the line with arrowheads is shorter than the other. When you impose lines on to the figures the lines imposed on the arrowheads is shorter than the lines in-between the feather tails. From this conflicting info we make a compromise and create an explanation of the figure that makes sense with the other information we know about the image by comparing each piece of info to the other

Ames Room Illusion: involves a trapezium-shaped room that is much longer and higher on one side than the other. When viewed through a peephole with one eye both corners of the room produce the same sized image on the retina and we perceive the corners to be the same size and that the room has a rectangular shape

Apparent Distance Theory: When two retinal images are the same size, but when one image appears to be at a larger distance, then the one that appears to be further away will be interpreted as larger because we’re limited to monocular cues only. This demonstrates the inability to maintain size constancy"

[iNerd]

Here are my notes which I used in preparation for my Unit1 SAC which I just completed 55minutes ago...it was piss easy..hoping for 27-30 out of 30.

Muller-Lyer illusion: A visual illusion, in which one of two lines of equal length, each of which has opposite shaped ends, is incorrectly perceived as being longer than the other.

Biological perspective:  “Eye movement” theory states that because the feather-tailed line in the illusion is longer it lengthens the eye movements required to view the line, therefore we perceive this line as longer. This theory has been rejected when researchers found that the illusion continues to be seen even when there is no eye movement at all.

Behavioral perspective: In 3D world we have grown accustomed to seeing corners everywhere and often use these and other angles and lines to judge depth and distance. The arrow headed line looks like the nearer, outside vertical corner of a room or building whereas the feather-tailed line looks like the farthest inside corner of a room.

Socio-cultural perspective: People like the Zulus in Africa live in non-carpentered worlds with roundish homes without all the familiar angles, corners  and edges of a Western 3D world. These Zulus are more likely to view the lines in their actual 2D forms and therefore perceive the lines as equal in length.

Cognitive :: ii didn't really understand it; good it didn't come up : )