Illusions What assumptions do we make about rooms? z90 degree angles zSize & distance (we make the false assumption that they are the same distance way) zTo fool us they distorted the shape of the room
St. Louis Arch zTaller than wider? zWider than taller?
Form perception Our brains do more then just register info, we filter & infer to make sense by discriminating what it is - form We organize and interpret meaning
What is it?
Perceptual Organization Form perception Figure and Ground--organization of the visual field into objects (figures) that stand out from their surroundings (ground); Reversible figures
What is it?
Perceptual Organization: Gestalt Grouping the perceptual tendency to organize stimuli into coherent groups
Gestalt grouping prin. Grouping Principles a)proximity--group nearby figures together b)similarity--group figures that are similar c)continuity--perceive continuous patterns d)closure--fill in gaps e)connectedness--spots, lines, and areas are seen as unit when connected
PerceptualOrganization: Grouping Principles
PerceptualOrganization: Closure Gestalt grouping principles are at work here.
PerceptualOrganization: Grouping Principles Gestalt grouping principles are at work here
Depth perception 1. Binocular cues a)retinal disparity images from the two eyes differ closer the object, the larger the disparity (floating finger sausage) b)convergence neuromuscular cue - two eyes move inward for near objects
2. Monocular Cues a)relative size smaller image is more distant b) Interposition (overlay) closer objects blocks distant object
Motion Perception 1.Stroboscopic movement - still pictures can be perceived as moving ( cartoons & film) 2.Phi phenomenon - 2 adjacent stationary lights blink on/off in succession are perceived as moving
Perceptual Constancy Perceptual Constancy perceiving objects as unchanging even as illumination and retinal image change color shape size
Size & distance p.239
Monster & Ponzo illusions zMonster - linear perspective, relative height; cues to distance & size zPonzo - we perceive the bar as farther away as being larger based on experience
Moon illusion zMoon looks larger at the horizon then it does high in the sky zExplanation: cues to objects distances at the horizon make the moon seem farther away zSimilar to the monster & ponzo illusion