Perception zSelective Attention focus of conscious awareness on a particular stimulus zhttps:// zhttp:// zhttp:// perception_shortfilmshttp:// perception_shortfilms

Testing Selective Attention

Selective Attention zSelective Attention means that at any moment, awareness focuses on only a limited aspect of all that we are capable of experiencing. For example, even if a stimulus figure can evoke more than one perception, we consciously experience only one at a time. zAnother example of selective attention: the cocktail party effect zalso limits our perception, as many stimuli will pass by unnoticed.

Inattentional Blindness What is Inattentional Blindness? Selective attention also limits our perception, as many stimuli will pass by unnoticed. This lack of awareness is evident in studies of inattentional blindness. Forms of this include: ychange blindness ychange deafness ychoice blindness

What is Choice Blindness zPetter Johansson and Lars Hall, the researchers who originally coined the term, people "...often fail to notice glaring mismatches between their intentions and outcomes, while nevertheless being prepared to offer introspectively derived reasons for why they chose the way they did." blindness/ blindness/

Obj. Describe the interplay between attention and perception. Answer the following question (in your own words) on the back of the paper that was placed on your desk: How does attention impact our perception? Use the following terms in your answer: zChoice-blindness zInattentional blindness zCocktail party effect zSelective attention zTop-Down

Perceptual Illusions Muller-Lyer Illusion-

Perceptual Illusions

Watch This: How Brains Learn to See zhttp:// n_how_brains_learn_to_seehttp:// n_how_brains_learn_to_see

Object Recognition zBlindness - brains_learn_to_see brains_learn_to_see zData-Driven Processing (look at the handout 6-4) b. Abe Lincoln (matched with objects in our long term memory and b.) the 1 st picture on the page (a cow) data-driven and conceptually driven processing z Visual agnosia – syndrome in which all parts of the visual field are seen, but are without meaning – Read The Man Who Mistook His Wife for a Hat, by Oliver Sacks zVisual object agnosia – no damage to the eye but unable to recognize familiar objects.

4.Simultagnosia – cannot pay attention to more than one stimulus at a time. Not being able to see objects simultaneously. 5.Spatial agnosia – trouble negotiating their way through the world (wrong turns, lost in own home)

Perceptual Organization- Gestalt zVisual Capture ytendency for vision to dominate the other senses zGrouping ythe perceptual tendency to organize stimuli into coherent groups

Perceptual Organization- Gestalt zGestalt- an organized whole ytendency to integrate pieces of information into meaningful wholes zGrouping Principles yproximity- group nearby figures together ysimilarity- group figures that are similar ycontinuity- perceive continuous patterns yclosure- fill in gaps yconnectedness- spots, lines and areas are seen as unit when connected

Perceptual Organization- Illusory Contours

Perceptual Organization zFigure and Ground organization of the visual field into objects (figures) that stand out from their surroundings (ground)

PerceptualOrganization- Grouping Principles

zGestalt grouping principles are at work here.

Perceptual Organization- Depth Perception zDepth Perception yability to see objects in three dimensions yallows us to judge distance zBinocular cues yretinal disparity ximages from the two eyes differ xcloser the object, the larger the disparity yconvergence xneuromuscular cue xtwo eyes move inward for near objects

Perceptual Organization- Depth Perception Visual Cliff

Perceptual Organization- Depth Perception zMonocular Cues yrelative size xsmaller image is more distant yinterposition xcloser object blocks distant object yrelative clarity xhazy object seen as more distant ytexture coarse --> close fine --> distant

Perceptual Organization- Depth Perception Relative Size

Perceptual Organization- Depth Perception

zMonocular Cues (cont.) yrelative height xhigher objects seen as more distant yrelative motion xcloser objects seem to move faster ylinear perspective xparallel lines converge with distance yrelative brightness xcloser objects appear brighter

Perceptual Organization- Depth Perception Perspective Techniques