Chapter 8: Motion Perception Flashcards
(24 cards)
Motion Detection
Ability to Detect motion is adaptively significant
-Predators Detect
-Prey Freeze
More than an image moving across the retina
Motion Agnosia
Inability to perceive motion
What kind of motion captures attention?
Motion Onset
Absolute Threshold of Motion
2-3 Minutes of arc
Real Movement
-Detection of movement in a physically moving object
-Absolute threshold depends on
-> Velocity
->Distance between points
Apparent Movement
-Perception of motion in separate items
-Illusory motion consistent with gestalt laws
Influenced by:
-Distance
-Interstimulus Interval
What is an example of apparent motion?
Ternus Illusion
Elemental Motion
Group Motion
Induced Movement
-Perception of motion in a stationary object due to motion of another object
-Can cause vection
Autokinetic Motion
-Stationary stimuli appear to move
-Ex: Leviant’s Enigma
Motion Aftereffect
-Moving pattern in one direction results in perceived motion of stationary item in opposite direction
-Suggests opponent-process neurons for motion
Reichardt’s Simple Motion Detection Circuits
-Simple motion detection neurons in V1
-Motion Sensitive based on inhibitory setups on the retina
Correspondence Problem
Is the stimulation of two photoreceptors due to
-One moving object?
-Two different objects?
Why does the correspondence problem exist?
The aperture problem
-Any complex V1 neuron sees a small part of visual field
V5/Medial Temporal Lobe
Specialized for detecting global motion
-Overall direction or pattern of movement across larger visual field
-Shown through Newsome’s study on monkeys
V1
Handles Local Motion
-Detects movement of individual elements
6 Eye Muscles Responsible for
Smooth Pursuit: Tracking moving objects smoothly
Saccades: Quick jumps between focus points
Micro saccades: Tiny, Involuntary shifts during fixation
Difficult to explain situations
1: Image of moving object is stationary on retina, but we correctly perceive it to be moving
2: Image of stationary object is moving along retina but we correctly perceive it to be stationary
Corollary Discharge Theory
“Motion continues in the same direction” Heuristic
If motion is ambiguous, the brain assumes the object will continue in the same direction
Occlusion Heuristic
If an object disappears, the brain assumes it continues along the same path unless there is evidence to the contrary
Shortest Path Constraint
When multiple paths are possible for perceived motion, the brain chooses the simplest/shortest (Gestalt)
Ecological Approach
