Perceiving depth and size

Question 1

What are the three cues for depth perception?

Answer 1

Oculomotor cues, binocular depth cues and monocular cues.

Question 2

What are oculomotor cues?

Answer 2

The involvement of movement of two muscle areas, convergence- the inward movement of our eyes as we look at nearby objects
accommodation- the changes in the shape of the lens as we focus on nearby objects.

Question 3

What are binocular depth cues?

Answer 3

Cues dependant on the information received from both eyes. Convergence can be classified as binocular cue. Main element of binocular depth is disparity.

Question 4

What is binocular disparity?

Answer 4

The difference in the position of the images in our two eyes.

Question 5

What is steropsis?

Answer 5

The perception of depth as a result of retinal disparity.

Question 6

How do some species have an evolutionary advantage due to fields of vision?

Answer 6

Their fields of view do not overlap and therefore have a wider visual field to spot more predators.

Question 7

What are monocular cues?

Answer 7

Cues provided only from one eye, two types, pictorial cues and movement based cues.

Question 8

What is occlusion?

Answer 8

Pictorial cue: When an object is partially being obscured, the one behind is being perceived as being further away.

Question 9

What are cast shadows?

Answer 9

Pictorial cue: Shadows cast by objects that can provide information regarding the objects location and depth.

Question 10

What is the depth cue of relative size?

Answer 10

Pictorial cue: When objects that are known to be equal size if an object can be perceived as smaller it is assumed to be further away.

Question 11

What is atmospheric perspective?

Answer 11

Pictorial cue: When objects are viewed through air or dust and fog it can cause distant objects to appear hazy or blurred, as a results they appear further away than sharp objects.

Question 12

What is Linear perspective?

Answer 12

Pictorial: Parallel lines in the world are associated with increasing distance.

Question 13

What is motion parallax?

Answer 13

Movement base cues: The idea that objects when moving in a car that are closer glide past rapidly whereas the further away they are the slower they move.

Question 14

What is size consistency and stored knowledge?

Answer 14

The idea that the brain has presumed knowledge about the size of a certain object and therefore when seeing it always presumes that it is the size it knows, unless something in the scenery suggests otherwise changing the perception. e.g. person standing next to giant chair.

Question 15

How do depth cues interact with perceived size and perspective?

Answer 15

If an aspect on an image that is made to look 3D is moved it can change the perceived size of the image.

Question 16

What did Holway and Boring do to investigate size perception?

Answer 16

Observer placed at the intersection of two hallways, a luminous test circle was in the right hallway, from 10- 120 feet away. A luminous comparison circle was in the left hallway 10 feet away.

Question 17

What is the size-distance scaling equation?

Answer 17

S=K(RxD) 
K-measuring agent constant
S- perceived size 
R- Retinal image size
D- Perceived distance.

Question 18

What is an Ames room?

Answer 18

A heavily distorted room that is used to create an optical illusion, viewed through one eye through a pinhole.

Question 19

Why does the moon seem larger on the horizon than it does in the sky?

Answer 19

Apparent distance theory: horizon moon is surrounded by depth cues while moon higher in the sky isn’t.
Horizon is perceived as further away than the sky called flattened heavens.

Question 20

What is the Muller-Lyer illusion?

Answer 20

The idea that a line with outwards fins appears longer than one with outwards although they are the same length.

>