Unit 4(G): Perceptual Organization and Interpretation Mr. McCormick A.P. Psychology

Do-Now (In Journal) What is an illusion? How can illusions influence and mislead our perception of a stimulus? Provide an example of a perceptual illusion that you have experienced.

Perceptual Organization What do you perceive when you observe this image? Why do you think you perceive two facial images?

Perceptual Organization Gestalt: An organized whole Tendency to integrate pieces of information into meaningful wholes

Form Perception Figure-ground: The organization of the visual field into objects (the figures) that stand out from their surroundings (the ground)

Form Perception Look at the images on Hand-Out 6-13: How does Figure 1 illustrate the concept of gestalt? What do you see when you look at Figure 2? What does this suggest about our perception? How does Figure 3 create a conflict of figure-ground? What ambiguous figures does your mind organize and reorganize in Figure 4?

Grouping After distinguishing the figure from the ground, our perception needs to organize the figure into a meaningful form using grouping rules

Grouping and Reality Although grouping principles usually help us construct reality, they may occasionally lead us astray.

Depth Perception Depth Perception: Ability to see objects in three dimensions although the images that strike the retina are two-dimensional Allows us to perceive distance

Depth Perception: Binocular Cues Why is it difficult to bring the tips of two pens together with one eye closed? How does the brain use retinal disparity to perceive distance? How do 3-D movies apply principles of binocular cues?

Depth Perception: Binocular Cues Depth perception enables us to judge distances. Gibson and Walk (1960) suggested that human infants (crawling age) have depth perception. Even newborn animals show depth perception. Visual Cliff

Depth Perception: Binocular Cues: Try looking at your two index fingers when pointing them towards each other half an inch apart and about 5 inches directly in front of your eyes. What do you see?

Depth Perception Binocular Cues: Monocular Cues: Convergence Retinal Disparity Relative Height Interposition Light/Shadows Texture/Detail Motion Parallax Linear Perspective Relative Motion

Perceptual Constancy Perceptual Constancy: Perceptual Set: Perceiving objects as unchanging (having consistent shapes, size, lightness, and color) even as illumination and retinal images change Perceptual Set: A mental predisposition to perceive one thing and not another

Perceptual Constancy: Shape Constancy

Perceptual Constancy: Color Constancy

Perceptual Constancy: Light Constancy The color and brightness of square A and B are the same.

Size-Distance Relationship The distant monster (below, left) and the top red bar (below, right) appear bigger because of distance cues.

Size-Distance Relationship: Ames Room Both girls in the room are of similar height. However, we perceive them to be of different heights as they stand in the two corners of the room.

Size-Distance Relationship: Ames Room The Ames room is designed to demonstrate the size-distance illusion.

3-D Sidewalk Illusions

3-D Sidewalk Illusions

3-D Sidewalk Illusions

3-D Sidewalk Illusions

3-D Sidewalk Illusions

Perceptual Set A mental predisposition to perceive one thing and not another. What you see in the center picture is influenced by mixing both pictures.

Perceptual Set Other examples of perceptual set. (a) Loch Ness monster or a tree trunk; (b) Flying saucers or clouds?

Influences of Perception

Review How do gestalts influence our perception? How do we use retinal disparity to understand depth? What does perceptual set suggest about our abilities to perceive? How do biological, psychological, and social-cultural influences affect our perception?

Homework Unit 4 Test: “Sensation and Perception” Chapter 5 Outline: “States of Consciousness”