Unit 5: Sensation & Perception Day 8: Gestalt, Inattention Blindness, & visual cues DAILY COMMENTARY (in a spiral notebook!): How good are you at noticing changes and new things? Use each of these terms in a sentence about your thanksgiving: Olfaction Absolute threshold Hypothalamus Cochlea Essential Question How do our senses detect the world? How does our brain perceive the world? Objectives (write this down!): I can: elaborate on and cite examples of the gestalt principle I can explain inattention and change blindness

Unit 5: Senation & Perception Day 8: Gestalt & Inattention Blindness SUBMIT: RJ 5.8 By Tomorrow: Sensation Book; All Unit 5 Reading Journals Today: DC Quiz discussion Notes FRQ Development Structured Review

Cocktail Party Effect Aspect of selective attention Ability to focus in on one sound/voice and tune out a variety of other sounds We ARE NOT capable of paying attention to multiple inputs at the same time http://www.youtube.com/watch?v=iO3jTl0WuS4

Video Links http://www.youtube.com/watch?v=FWSxSQsspiQ http://www.youtube.com/watch?v=VkrrVozZR2c http://www.youtube.com/watch?v=IGQmdoK_ZfY

Inattentional Blindness Inattentional blindness refers to the inability to see an object or a person in our midst. Simmons & Chabris (1999) showed that half of the observers failed to see the gorilla-suited assistant in a ball passing game. Daniel Simons, University of Illinois

Change Blindness Change blindness is a form of inattentional blindness in which two-thirds of individuals giving directions failed to notice a change in the individual asking for directions. © 1998 Psychonomic Society Inc. Image provided courtesy of Daniel J. Simmons.

Gestalt Principle The brain automatically organizes visual inputs into a meaningful organized whole Closure – automatic completion of incomplete images Proximity – grouping together of things near each other Similarity – grouping similar objects together (assumption that players with same color jerseys are on same team)

Gestalt Principle The brain automatically organizes visual inputs into a meaningful organized whole Continuity – we want things to fit together, even if they don’t; we connect a line that has a gap in it. Connectedness --

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

Grouping & Reality Although grouping principles usually help us construct reality, they may occasionally lead us astray. Both photos by Walter Wick. Reprinted from GAMES Magazine. .© 1983 PCS Games Limited Partnership

Binocular Cues Retinal disparity: Images from the two eyes differ. 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. You will see a “finger sausage” as shown in the inset.

Binocular Cues Convergence: Neuromuscular cues. When two eyes move inward (towards the nose) to see near objects and outward (away from the nose) to see faraway objects. OBJECTIVE 6| Describe two binocular cues for perceiving depth, and explain how they help the brain to compute distance.

Monocular Cues Relative Size: If two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away. OBJECTIVE 7| Explain how monocular cues differ from binocular cues, and describe several monocular cues for perceiving depth.

Monocular Cues Interposition: Objects that occlude (block) other objects tend to be perceived as closer. Rene Magritte, The Blank Signature, oil on canvas, National Gallery of Art, Washington. Collection of Mr. and Mrs. Paul Mellon. Photo by Richard Carafelli.

Monocular Cues Relative Clarity: Because light from distant objects passes through more light than closer objects, we perceive hazy objects to be farther away than those objects that appear sharp and clear.

Monocular Cues Texture Gradient: Indistinct (fine) texture signals an increasing distance. © Eric Lessing/ Art Resource, NY

Monocular Cues Relative Height: We perceive objects that are higher in our field of vision to be farther away than those that are lower. Image courtesy of Shaun P. Vecera, Ph. D., adapted from stimuli that appered in Vecrera et al., 2002

Monocular Cues Relative motion: Objects closer to a fixation point move faster and in opposing direction to those objects that are farther away from a fixation point, moving slower and in the same direction.

Monocular Cues Linear Perspective: Parallel lines, such as railroad tracks, appear to converge in the distance. The more the lines converge, the greater their perceived distance. © The New Yorker Collection, 2002, Jack Ziegler from cartoonbank.com. All rights reserved.

Monocular Cues Light and Shadow: Nearby objects reflect more light into our eyes than more distant objects. Given two identical objects, the dimmer one appears to be farther away. From “Perceiving Shape From Shading” by Vilayaur S. Ramachandran. © 1988 by Scientific American, Inc. All rights reserved.

Motion Perception Motion Perception: Objects traveling towards us grow in size and those moving away shrink in size. The same is true when the observer moves to or from an object. OBJECTIVE 8| State the basic assumption we make in our perceptions of motion, and explain how these perceptions can be deceiving.

Apparent Motion Phi Phenomenon: When lights flash at a certain speed they tend to present illusions of motion. Neon signs use this principle to create motion perception. One light jumping from one point to another: Illusion of motion. Two lights flashing one after the other.

Class Work Complete the design of your Free Response Question, including a scoring rubric. Rubric must provide a specific guide showing what types of answers will score for each point, and what will not score. Google: “ap psychology frq scoring guide” to see examples If done: extra credit -- Design an experiment to test selective attention in people. Research: Can people effectively multi-task?

Exit Pass Give examples demonstrating three of the gestalt principles Then submit Daily Commentary notebook for grading. Prepare for test Wednesday.