1. Perception Chapter 6 Mr. McElhaney

2. “Seeing” Gregory explains vision: Pay attention to the following: 1. Gestalt, Foreground, Background, Silhouette 2. How does the eye select, filter and become conscious or make sense of visual world? 3. How does the perceptual system work? 4. What is the role of experience in perception? 5. What are illusions?

3. Questions to be answered  What is the role of experience in perception?  What is the role of culture ?  How does the mind make meaning of the stimuli from the environment?

4. Perception  Defined: is the process through which people actively use knowledge and understanding of the world to interpret sensations as meaningful experiences.  Making sense of visual stimuli  How we assemble sensations into meaningful patterns  Perception is empirical= experiential

5. Perceptual System Automatically distinguishes - Automatically distinguishes - Figure/ground stimuli into patternsFigure/ground stimuli into patterns Groups StimuliGroups Stimuli Laws or Principles: Laws or Principles: ProximityProximity SimilaritySimilarity ContinuityContinuity ClosureClosure Common Fate – (visual) objects moving in unisonCommon Fate – (visual) objects moving in unison Synchrony- (Multiple Senses) stimuli that occur at the same time appear to belong togetherSynchrony- (Multiple Senses) stimuli that occur at the same time appear to belong together Common Region- location boundaryCommon Region- location boundary ConnectednessConnectedness

6. Constancies  Perceptual Constancy Perception needs experience Perception needs experience Must be familiar with objects to use their size to judge distance Must be familiar with objects to use their size to judge distance  Size Constancy Perceived size of object remains the same even though size on the retina changes Perceived size of object remains the same even though size on the retina changes  Shape Constancy Shape of an object remains constant Shape of an object remains constant Alcohol impairs Alcohol impairs  Brightness Constancy Brightness of objects appear to be the same if surrounding objects are illuminated- light Brightness of objects appear to be the same if surrounding objects are illuminated- light

7. Perceptual Organization  Contrasts help perception Object and plain background Object and plain background  Figure Ground- perception is first  Reversible figure ground Perception is reversed Perception is reversed Background is more visible Background is more visible

8. Gestalt Principles  We have a tendency to complete shapes into whole units  Factors of Perception that bring order to perceptions: Visual depictions can be designed to be perceptually efficient. Visual depictions can be designed to be perceptually efficient.

9. Factors of Perception Gestalt Principles : “ The whole is greater than its parts.”  Nearness- items near are grouped together items will be seen in groups  Similarity- perceived size/shape color form tend to be grouped together  Continuation- continuity- tend toward simplicity- it’s easier to visualize wavy line than complex rows  Closures- tendency to complete a figure so that it has an overall form  Common region- stimuli found in a common region or area seen as a group Used in everyday patterns Used in everyday patterns

11. Camouflage  Breaks up foreground organization images  also known as cryptic coloration or concealing coloration, allows an otherwise visible organism or object to remain indiscernible from the surrounding environment. © E.R. Degginger/Animals Animals

12. Perceptual Hypothesis  We find meaning and organize visual perceptions from a distance  We make judgments (hypotheses)  When we get closer the hypothesis is proved or disproved  We expect and understand based on experience we have preexisting ideas

13. Necker’s Cube  Ambiguous stimuli Patterns that allow more than one interpretation Patterns that allow more than one interpretation  Brain interprets patterns  We actively construct meaningful perceptions/ not passive  Problem- Conflicting information prevents stable perception

14. Depth Perception  Ability to perceive 3 dimensional space  Nativist= inborn ability  Or  Empiricists = experience based  Depth perception is both

15. Visual Cliff  The concept of testing depth perception in babies  Can babies identify Depth Cues? Features of the environment and messages from the body that supply information about distance/depth Features of the environment and messages from the body that supply information about distance/depth

16. Study found that Infants have some innate depth perception. Implications are that humans have both – innate and experiential abilities

17. Why do infants and babies fall off beds and things?  Depth perception and motor skills have not integrated yet 

18. Depth Perception  Perception of distance Stimulus Cues Stimulus Cues Partly a physical structure of the Visual System Partly a physical structure of the Visual System

19. Depth Perception: Muscular Cues  Monocular or Binocular  Sensations from muscles attached to each lens flow back to the brain  Accommodation- (using muscles) bending of lens to focus on nearby object  Convergence= Distant vision = parallel within 50’ eyes converge Controlled by muscles feed info to the brain helps judge distance Controlled by muscles feed info to the brain helps judge distance

20. Convergence

21. Muscular Cue: Stereoscopic Vision=2 eyes  Focusing of image by two eyes = 3 dimensional sight  Retinal Disparity (Binocular cue)= two eyes, see the world differently “Discrepancy in images that reaches right and left eye” (3 D movies pg 221) “Discrepancy in images that reaches right and left eye” (3 D movies pg 221) Produces Depth Produces Depth  One eyed people can learn to perceive depth

24.  Random Dot Stereogram-  Patterns of dots that produce an illusion of depth  Shows the brain is very sensitve to any mismatch

26. Pictorial Cues for Depth  Linear Perspective  Relative size  Height in picture plane  Light and shadow  Texture gradient  Overlap  Aerial perspective  Relative Motion

27.   Fig. 6.14 (a) Linear perspective. (b) Relative size. (c) Light and shadow. (d) Overlap. (e) Texture gradients. Drawings in the top row show fairly “pure” examples of each of the pictorial depth cues. In the bottom row, the pictorial depth cues are used to assemble a more realistic scene.

28. The Moon Illusion Moon IllusionMoon Illusion  Perceiving the moon as larger when it is low in the sky;  Problem: the moon is closer when the directly overhead  The brain thinks the low moon is larger because of Depth Cues  Horizon makes moon larger and closer Apparent distance Hypothesis: Existence of depth cues causes us to make distant objects seem closer.

29. Perceptual Learning  Refers to experiences that cause changes in the brain that alter how we process info  We learn to focus on one part of stimuli  We learn to tell the difference between stimuli

30. Perceptual Habits  Through Experience  We establish habits of perception  Patterns of organization and attention Perceptual Features- are learned and the brain becomes sensitive to: Lines, shapes, edges, spots, and colors

31.  appears square, distorts proportions= Both Perceptual Habits and Perceptual Learning  Ames Room- appears square, distorts proportions= Both Perceptual Habits and Perceptual Learning

32. Perceptual Habits continued  Other Race Effect  Inverted vision= human brain can adapt Through active movementThrough active movement People need to be active to adaptPeople need to be active to adapt

33. Examples of Illusions

34. Illusions: Size Distance Variance  The size of an object’s image is precisely related to its distance from the eye  Two objects make images the same size

35. Perception cannot occur without attention  Motives for one stimulus will make perception for that stimulus more sensitive  Selective Attention: we give some messages priority.  Divide Attention: Causes us to divide attention among tasks that require more or less effort

36. Types of stimuli that impact attention  Intense stimuli commands attention (brighter, louder, larger- Advertising psych) (brighter, louder, larger- Advertising psych)  Repetitious Stimuli- grabs attention  Contrast or changing stimuli gets attention

37. Other Factors to Attention  Inattentional Blindness Click first Click firstClick first  The occurrence where when focused on a specific item we miss other information and items  Habituation= boredom, we respond less to unchanging stimuli  Habituation= boredom, we respond less to unchanging stimuli Connected to Adaptation- decrease the actual number of sensory messages sent to brain Connected to Adaptation- decrease the actual number of sensory messages sent to brain

38. Biological Receptivity  Orientation Response: prepares us to receive information Pupils enlarge Pupils enlarge Brain patterns shift Brain patterns shift Breathing stops Breathing stops Blood flow to the head increases Blood flow to the head increases Physical turn toward stimulus Physical turn toward stimulus “Double Take” “Double Take”

39. Perceptual Expectancies  Expecting stimuli in a certain manner  “Past experiences, motives, context”  “Prepares you to perceive in certain ways.”  “We see what we expect to see.”  Can be created by suggestion

40. Perceptual Expectancies  Bottom Up Processing- Feature analysis of info with sensory units build upward to a complete perception  A puzzle in pieces  Feature Analysis (Form, Color, Motion, lines, shapes, colors)  Analysis of info with sensory units  Build upwards to a complete picture

41. Top Down Processing-  Top Down  A complete picture (a known puzzle)  pre-existing knowledge used- to rapidly organize features (small units) to a whole Preexisting knowledge used to organize feature s to a whole  Gestalt  Influenced by expectancy and motivation  Schemas- based on past experience can create a perceptual set  (Perceptual Set = the readiness to perceive stimuli in certain ways.)  Bottom Up = Stimulus Driven  Relying on specific details information from sensory receptors that are assembled into a whole.  Stimulus characteristics:  Sudden Changes in light or color,  Movement  Appearance of Unusual shapes  Knowldege and beliefs create expectations- that give meaning to the features. Interpretations that are suggested can be recognized

42. Perceptual Categories  Experiences are sorted into categories  Labels impact the way we perceive others- Classes Classes Types Types Groups Groups

43. Eyewitness Testimony  Is often incorrect  When a person is surprised, threatened, or under stress are especially prone to distortion

44. Maslow and Perception  Found some people perceive themselves and others with great accuracy.  Characteristics: Lack Self ConsciousnessLack Self Consciousness Not criticalNot critical Not evaluatingNot evaluating  Problem of Habituation- boredom, responding less to stimuli  Need to Dishabituate- reverse habituation = pay attention Examples of: Mother and infant Child @ Christmas Two people in love

45. How to Improve Perception  Remember perceptions are reconstructions of reality  Break perceptual habits and interrupt habituation  Shift adaptation levels and broaden frames of reference by seeking out of the ordinary experiences  Beware of perceptual sets  Be aware of the ways in which motives and emotions influence perceptions  Make a habit of engaging in reality testing.  Pay attention