Visual Illusions Flashcards
visual perception
the activity by which an organism uses its eyes to obtain information about its environment and about itself in relation to its environment
visual illusions
when visual perception makes mistakes that are large enough to be surprising
- help predict circumstances under which vision fails
object recognition
what things are
properties of things
size, shape, color, orientation
space perception (spatial layout)
where things are; how things are arranged relative to each other
absolute (metric) egocentric distance
where things are
selective adaptation (response to motion)
- motion detectors (neurons) become sensitive/fatigued to a stimulus after prolonged exposure
- neurons adapt by decreasing rate of firing and firing less when stimulus is presented again
- adaptation causes us to be perceptually less sensitive to that stimulus
spiral aftereffect
- neurons are being stimulated at different places on retina and fatigued
- each receptive field is only looking at one small part of retinal image (failure to see big picture leads to illusions)
aperture illusion
- square is moving up but edge appears to be moving on a diagonal
- component of motion parallel to the edge cannot be seen; produces no vision motion
- neurons in V1 are not responding to the actual motion, only a component of motion (inaccurate, estimated motion)
breathing square illusion
- appears to be contracting but is rigid
- shapes of openings bias the combination process
motion binding
visual system’s ability to connect together the separated parts of a moving object
- varies when some parts are hidden by occluders
geometrical illusions
simple line figures that produce large errors in perception
linear perspective
2-D convergence: if lines in a 3D scene are parallel and slanted away from viewer, the lines will converge toward a vanishing point; creates depth perception in a flat picture
motion parallax
when an observer moves relative to a 3D scene, the images of things that are closer move more than the images of things that are farther away
concave vs convex
concave = curved away from you
convex = curved toward you