Depth and distance

Question 1

Depth perception

Answer 1

the ability to see three-dimensional space and to accurately judge distances

Question 2

Depth cues

Answer 2

messages sent from the environment or our own body and provide information to help us perceive depth or distance so that we can perceptually locate objects and perceive how far away they are

Question 3

Binocular cues

Answer 3

– require both eyes to work together to provide the brain with information about depth and distance. Person with one eye can still judge depth, just not as well.

Question 4

1) Retinal disparity

Answer 4

• refers to small discrepancies between an image that reaches the left eye and an image that reaches the right eye
• based on our eyes being about 6.5 centimetres apart
• each retina receives slightly different image
• brain fuses separate images into one overall image
• overlapped image results in stereoscopic vision (3-D sight)

Question 5

2) Convergence

Answer 5

• involves both eyes simultaneously turning inwards as an object moves closer (within approximately 7 metres) in order to maintain focus on the object
• controlled by a group of muscles attached to eyeball
• when these muscles tense or relax they feed info on eye position to the brain to help it judge distance
• when looking at something further than 7 m. eyes are parallel

Question 6

Monocular cues

Answer 6

require information from one eye only

Question 7

1) Accommodation

Answer 7

• involves ciliary muscles contracting and relaxing to focus the lens
• sensations from moving muscles sent to brain and interpreted
• help us judge distance within 20 cm- 3 m.

Question 8

2) Pictorial cues

Answer 8

• create an impression of depth on a flat 2-D surface where depth does not exist

Question 9

i) linear perspective

Answer 9

• apparent convergence of parallel lines

- creates impression of increasing distance

Question 10

ii) relative size

Answer 10

• smaller retinal image of two objects perceived as further away, larger = closer
• strongest when we are familiar with actual size of objects

Question 11

iii) interposition

Answer 11

• occurs when one object partially blocks another and is perceived as being in front of, therefore closer than, the object it covers
• also known as overlap

Question 12

iv) texture gradient

Answer 12

• refers to the surface features of an object becoming smaller and less detailed the more distant the object becomes

Question 13

v) height in the visual field

Answer 13

• refers to the height of objects in the visual field (either above or below the horizon) acting as a depth cue
• objects placed higher in a picture appear more distant than object below
• objects closer to horizon appear further away
• however, objects placed in the sky and close to the horizon appear closer