Motion Perception

Function of Motion Perception

Motion perception helps break camouflage, attract attention, segregate objects, interpret events, determine structure, and interpret actions. = motion attracts attention which helps segregate objects from background

Interpret Events (via Motion)

Inferring causality relationships and even social relationships by seeing how objects interact.

Structure From Motion

Inferring the shape of a moving object = kinetic depth effect. e.g. motion reveals 3D shape

Point-Light Walkers

Created by placing lights on a person’s joints and having them perform an action, allowing humans to guess the action.

Akinetopsia

A condition where a person is no longer able to perceive motion, often due to brain damage.

Ways We Perceive Motion

Real motion, illusory motion (static image and apparent motion), motion aftereffects, and induced motion (moving background causes stationary object ot appear to move)

Apparent Motion

Occurs when a series of stationary images are presented in succession to give the impression of movement. Must be spaced closely together in time and location. Most insensitive to colour

Korte’s Third Law of Apparent Motion

As separation increases alternation rate needs to decrease to maintain the perception of motion.

Motion Aftereffect

After staring at a moving stimulus like a waterfall and then shifting gaze to a stationary object, the object appears to move in the opposite direction.

Induced Motion

A nearby object affects the perceived motion of another object or causes it to appear to move.

Motion Induced Change Blindness

Motion can cause things to disappear = motion removes transient signals of single object change as all objects have transient signals while moving

Motion Illusions (General)

Contrast affects motion perception

• higher contrast objects appear to move feaster

• lower contrast objects appear to move more slowly

Aperture Problem

If you can’t see the ends of a line, the perceived movement of a line is ambiguous