Depth + Motion Perception

Interposition/Occlusion

Interposition/Occlusion

= a near object covers/blocks an object farther away

Relative Size

= far-off objects look smaller than close objects do

(when close objects are the same physical/actual size)

Familiar Size

= we know how large familiar objects are, so we can tell ow far away they are by size of their retinal images

ex. being able to tell how far a person is (gets messed up if it’s like a comically large cardboard cutout``)

Detail/Aerial Perspective

= the further away an object is, the more blurry it is

(due to layers of atmosphere)

Linear Perspective

= parallel lines appear to converge in the distance

Texture Gradient

= as a uniformly textured surface recedes, its texture continuously becomes denser/smoother-looking

Position Relative to the Horizon

= for equal-size objects below the horizon, the one that appears higher in the vision field is perceived as being farther away

Motion Parallax

= when observer moving in a vehicle and looking out a window, nearer objects in scenery appear to be moving past faster than those farther in the distance

Visual Cliff

= research paradigm to test development of monocular depth perception in young children

ex. children show apprehension crossing glass where the appearance of a cliff exists

Binocular Disparity

= because 2 eyes are offset, they produce 2 diff images on retina, so brain uses disparity to calculate depth

• far object = not much disparity

• close object = lots of disparity

ex. if bring finger closer to face and close each eye, finger shifts around more the closer it is to eyes

Convergence

= looking at closer objects causes our eyes to converge

• brain uses this info to calculate depth

• when eyes view near object, muscles move eyes toward each other (strain)

Induced Movement

= assumption based on experience that smaller objects must be moving across larger one

ex. usually when we see a ball rolling across a table, we think ball is the one moving, not the table moving underneath a stationary ball

a misinterpretation of this illusion → the bigger object is moving, but brain assumes otherwise

ex. at traffic light and the big truck next to you starts moving forward and you hit the brakes harder, thinking you are going backward

Stroboscopic Movement

= rapidly flashing stationary pictures seem to move continuously

Phi Phenomenon

= set of rapidly flashing lights in slightly different places make it seem like light is moving

• similar to stroboscopic movement but for lights