Perception: Uses top-down processing The process of organizing and interpreting sensory information Module 10

Organizational Principles Module 10: Perception What important contribution did the Gestalt psychologists make to the study of human perception?

Gestalt The “whole,” or the organizational patterns that we tend to perceive Gestalt psychologists stressed that the whole is greater than the sum of its parts. By breaking experiences into their basic parts, something important is lost.

A Gestalt Image ~lglenn/gestaltimages.htmlhttp://faculty.uca.edu/ ~lglenn/gestaltimages.html edu/cgboer/gestalt.ht mlhttp://webspace.ship. edu/cgboer/gestalt.ht ml Notice how it messes with your perception, and how you can see many different things: –The whole is different then the sum of the parts!

Gestalt Organizational Principles: Figure-Ground Relationships Module 10: Perception How do people determine figure and ground, and why is this important?

Figure-Ground: Get out textbook and flip to Mod 10 to see pics! Gestalt psychologists say we naturally organize our environment into figure-ground relationships. The perceptual tendency to organize stimuli into objects (the figures) that stand out from their surrounding (the ground) –The figure is the object(s) that stands out or draws one’s attention. –The ground is the background.

Gestalt Organizational Principles: Grouping Principles Module 10: Perception Describe the principles of similarity, proximity, closure, and continuity.

Grouping Gestalt psychologist’s believe people are pre-disposed to grouping. –Placing items into understandable sets. Several principles of grouping include: –Similarity- Closure –Proximity- Continuity

Grouping - Similarity The tendency to place items that look similar into a group How would you group these items? Triangles? Circles? Rows 1 through 3?

Grouping - Proximity The tendency to place objects that are physically close to each other in a group How would you group these?

Grouping – Closure The tendency to look at the whole by filling in gaps in a perceptual field –Look at page 186 for closure and the blind spot! Are these shapes or just dashes?

Grouping – Continuity The tendency to perceive that movement of an object continues once it appears to move in a particular direction Do these lines continue or stop at the end of the slide?

Depth Perception Module 10: Perception What is depth perception, and how does it affect our lives?

Depth Perception The ability to see in three dimensions and judge distances

Visual Cliff A laboratory device for testing depth perception in infants and young animals –Infants are reluctant to crawl past the “edge” of the visual cliff Other animals had similar results. Suggests that depth perception, to some extent, is inborn

Depth Perception: Binocular Depth Cues Module 10: Perception What are the two major binocular depth cues, and how do they help us to perceive depth?

Binocular Cues 1.) Retinal Disparity Depth cues that require the use of both eyes Two types: Pass around Alexis’ Baby Toy –3-D Viewmaster A binocular depth cue resulting from slightly different images produced by the separation of the retinas in the left and right eye Is most effective when the item is quite close to the person –Hidden images & monster with cookie.

#2. Convergence A binocular depth cue related to the tension in the eye muscles when the eyes track inward to focus on objects close to the viewer The more tension in the eye muscle, the closer the object is Works best at close distances Try this: –Extend your arm and look at your fingers in front of you –Slowly bring your fingers to your eyes –What do you feel/notice?

Binocular Depth Cues: Finger Sausage

Extra Sensory Perception: Fill out 10-2 Handout I’m going to read your mind!!!!

Extra Sensory Powers Choose a number between 1 and10 Multiply that number by 9 –If the result is more than one digit, add them together Subtract 5 Find the letter in the Alphabet it equates to –1 = A Pick a country that begins with that letter Pick an animal that begins with the second letter of the country Write down the animal’s color Concentrate on your color

Depth Perception: Monocular Depth Cues What cues let us calculate depth using only one eye, and how do they let us calculate depth? Module 10: Perception

Monocular Cues Depth cues that require the use of only one eye Monocular depth cues include: relative size, relative motion, interposition, relative height, texture gradient, relative clarity, and linear perspective.

Monocular Depth Cues – Relative Size Using the perceived size of a familiar object to determine depth The larger the object appears, the closer the object is to the viewer.

Monocular Depth Cues – Relative Motion A person who is moving can determine depth by focusing on a distant object. –Objects further away than the object of focus will appear to move in the same direction as the subject is moving. –Objects closer than the object of focus will appear to move in the opposite direction.

Relative Motion

Monocular Depth Cues: Pgs Interposition Method of determining depth by noting that closer objects partially obstruct the more distant objects Also called “overlap” Relative Height Method of determining depth by noting that distant objects appear higher in your field of vision than do closer objects Texture Gradient Method of determining depth by noting that distant objects have a smoother texture than nearby objects Relative Clarity Method of determining depth by noting that distant objects are less clear than nearby objects Tends to work outdoors Linear Perspective Method of determining depth by noting that parallel lines appear to converge in the distance The lines appears to eventually merge on the horizon.

Motion Perception Module 10: Perception What might cause us to perceive motion when nothing is moving?

Stroboscopic Motion The illusion of motion by the rapid projection of slightly changing images –The concept a motion picture uses The photo below is many still images put together (A FLIPBOOK!)

Phi Phenomenon The illusion of motion when fixed lights are turned on and off in a sequence hill.com/sites/ /student_view0 /chapter8/phi_phenomenon_activity.htmlhttp://highered.mcgraw- hill.com/sites/ /student_view0 /chapter8/phi_phenomenon_activity.html

Perceptual Constancy: Perceiving the size, shape, and lightness of an object as unchanging, even as the retinal image of the object changes. The understanding that objects usually remain the same Module 10: Perception What is the value of perceptual constancy in our lives?

Perceptual Constancy: Size Constancy A person’s understanding that as an object moves further or closer to them its actual size stays the same as an object appears to become larger we realize it is getting closer, not bigger. As an object appears to become smaller we realize it is moving farther away, not getting smaller. Module 10: Perception

Size Distance Relationship

Perceptual Constancy: Shape Constancy Module 10: Perception

Shape Constancy The understanding that an object’s shape remains the same even though the angle of view makes the shape appear changed

Perceptual Constancy: Lightness Constancy The ability to see an object as having a constant level of lightness no matter how the lighting conditions change. Example: What color does computer paper appear to be in a room lit by fluorescents, sunlight, no lights? Module 10: Perception

Module 10: Perception Perpetual Set A mental predisposition to perceive something one way and not another Example of top-down processing Influence of the “power of suggestion” (subliminal perception) Guided by schemas: concepts or mental frameworks that organize and interpret information

Context: How does context influence our perceptions? The setting or environment in which we interpret sensory stimuli I once caught a fish “THIS BIG”! Often, the best fishermen hold their trophies closer to the camera to make them appear…

Illusions: Misinterpreting sensory stimuli Help researchers understand how sensation and perception normally works Module 10: Perception

Müller-Lyer Illusion

Most people think segment AB equals BC. In reality AB is much longer than BC.

Müller-Lyer Illusion Which wall looks longer?

Müller-Lyer Illusion

Ames Room Illusion: Secret Revealed (See book image)