Class Notes (807,350)
Canada (492,715)
Psychology (3,452)
PSY280H1 (47)

chap 8 textbook notes

2 Pages
Unlock Document

University of Toronto St. George
Kristie Dukewich

CH8 – PERCEIVING MOTION  Akinetopsia – motion agnosia, motion blindness o OPTIC ARRAY – the structure created by the surfaces, textures and contours of the environment o OPTIC FLOW – the movement of elements of the scene relative to the observer (movements into the plane of depth)  GRADIENT OF FLOW – objects closer to the observer moves faster than objects move faster than objects further away  FOCUS OF EXPANSION – in this point of view, the focus of expansion  location where there’s no movement  VECTION – illusion of self motion caused by moving visual cues  Ex. sitting in a car in traffic and car to the side moves first, feeling of own car moves back  more pronounce if more visual field is filled up  more pronounce if aligned with focus of expansion but compensated by eye movement Problems w/ visual motion  It’s not just about an image moving across the retina Usefulness of visual motion o SELF-MOTION – images move across the retina but motion is not  1. Motion grabs attention perceieved o Stimulates PARASOL GANGLION CELLS (sensitive)  triggers shift of o Tracking a moving object: motion perceived in the absence of image attention/eye-movements in the SUPERIOR COLLICULUS (automatic) movement across the retina  2. Motion provides information about 3D shape of an object o Structure from motion  3. Motion provides figure-ground separation o Based on: LAW OF COMMON FATE – objects move in the similar direction are grouped together, not 100% associated w/ figure ground separation  4. Motion allows interaction with the environment o Catching a baseball  Self-induced motion o Assists in locomotion through the environment o Provides information about the relative depth of objects (motion parallax) o Self-induced motion: visual vs. vestibular information  VESTIBULAR SYSTEM – a set of 5 organs located in each inner ear, sense head motion and orientation with respect to gravity  For balance  Effect: clear vision during motion  VISUAL INFORMATION overrides vestibular cues  motion sickness from conflicting signals from visual systems and vestibular system  visual system  moving, but vestibular system  not moving b/c not self induced motion o MOTION PARALLAX – moving in parallel to the plane of depth  things closer to the observer move faster than things at the distance  tell a relative depth of the objects  refer to motion parallax when moving parallel to plane of depth  more about information relative to objects in the environment, tells more about objects in the environment rather than your relative position o Self-induced motion: time to collision  TIME TO COLLISION – the time required for a moving object to hit a stationary object (distance/rate)  more to do w/ the change in size of object on the retina than our estimate of distance or rate (tau)  TAU – the ratio of retinal image size at any moment compare to the rate at which the image is expanding  APPARENT MOTION – motion perceived in the absence of image  time to collision is proportional to tau movement across the retina  Requires information from optic flow w/o having to o Vision updates btwn 8 – 32 times per second (Hz) measure distance or rate  low end 8 = not checking very often, for perceive form  Can be calculate quite quickly, one of the cues used to information avoid collision  high end 32 = limit for flicker perception, presenting changing in  Neurons in
More Less

Related notes for PSY280H1

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.