Lecture 15 Flashcards
Motion
Keeps us updated to perceive shapes; determine our direction; perceive other people’s moods
Survival in Environment
predators use movement to hunt prey; if prey reduces motion it will less likely be found
Akinetopsia
Blindness to motion; problem following dialogue bc cannot see lips moving
Attentional capture
Motion attracts attention to the moving object; only works if you’re consciously looking for something or it is occurring in peripheral vision
Real motion
An object is quite literally physically moving
Illusory motion
Stimuli is not moving but motion is perceived
Apparent motion (type of illusory motion)
Stationary stimuli are presented in slightly different locations; basis of movement for movies and tv shows
Induced motion (type of illusory motion)
Movement of one object results in the perception of movement in another object; ex - stationary moon and moving clouds
Motion aftereffect (type of illusory motion)
- observer looks at movement of one y for 20-60 sec
-look at stationary object - movement occurs in the opposite direction of og movement
Real and Apparent Motion
Perception of motion is related to the same brain mechanisms
Object moving and observer is stationary
image moves across retina stimulating receptors one after another causing us to perceive motion
Object moving and observer follows
image is stationary of retina bc of tracking movement
Observer moves through stationary environment
Image of environment moves across retina but environment is still perceived as stationary
Optic array
Structure created by surfaces, textures, and contours which change as the observer moves through the environment
Global optic flow
Overall movement of optic array, indicates that observer is moving and not the environment
Reichardt detectors
Neurons that fire to movement in one direction
Corollary discharge theory
Movement perception depends on three signals
Image displacement signal (IDS)
Occurs when an image is moving across receptor in retina
Motor signal (MS)
signals sent from brain to eye muscles
Corollary discharge signal (CDS)
copy of the motor signal but is sent to different area of brain
Movement perceived when comparator receives input from:
-corollary discharge signal
-image displacement signal
Movement not perceived when comparator receives signal from
Both CDS and IDS at the same time
Real-movement neuron
Only responds when stimulus moves, doesn’t respond when the eye moves, thus it must be receiving CDS
