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Perception

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Perception

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  1. Perception The process of organizing and interpreting information, enabling us to recognize meaningful objects and events.

  2. Perception • The active process of selecting, organizing, and interpreting the information brought to the brain by the senses • Perception is the way we interpret sensations and therefore make sense of everything around us • Example: • 7’9” vs. 6’9”

  3. Top Down Processing • Processing information from the senses with higher level mental processes using our experiences and expectations • Using your background knowledge to fill in the gaps • Examples: • Grouping

  4. Gestalt Psychology • Gestalt - focused on how we GROUP objects together as an organized whole. • Whole exceeds the sum of the parts • Example: Necker cube – Do you see circles with white lines or a cube? Do you see the x in the center in the front edge or the back?

  5. Figure Ground Relationship Figure –ground - Our first perceptual decision is what in the image is the figure and what is the background. Example: At an assembly, Ms short speaking is the figure, ground is people, curtain etc. on stage behind her

  6. Grouping • Grouping – tendency to organize stimuli into coherent groups and not isolated elements. • Examples closure

  7. Grouping • Proximity - group objects that are close together as being part of same group • Example – three girls standing in the hallway next to each other • Similarity - objects similar in appearance are perceived as being part of same group • Example – black toy poodles and red toy poodles are seen as two different groups of dogs • Continuity - objects that form a continuous form are perceived as same group • Example – Geese flying south form a “V” • Connectedness – objects that are uniform and linked are perceived as a single unit • Example – beads on a necklace • Closure - like top-down processing…we fill gaps in if we can recognize it • Example – IBM Logo

  8. Who emphasized that the whole may exceed the sum of its parts? • Evolutionary Psychologists • Parapsychologists • Behaviorists • Gestalt Psychologists • Humanistic Psychologists 0 of 24

  9. The perceptual tendency to group together stimuli that are near each other is called • Interposition • Proximity • Similarity • Closure • Retinal Disparity

  10. A floating sea vessel is to the ocean water as ____________ is to _____________. 24 • Light and shadow; relative height • Closure; continuity • Proximity; similarity • Top down; bottoms up • Figure; ground 0

  11. Depth Cues • Depth Perception • visual ability to see the world in 3-D even though images strike retina in two dimensions and • Ability to perceive the distance to an object • Visual Cliff Experiment- Eleanor Gibson • Crawling experience helps with depth perception • Depth perception is partially innate • See depth by using two cues • Examples • Monocular Cues • Binocular Cues

  12. Binocular Cues • Binocular cues – depth cues that depend on the use of two eyes. • Used to judge distance of object up close. • Examples: • Retinal Disparity - as an object comes closer to us, the differences in images between our eyes becomes greater. • 3-D Movies – simulate retinal disparity • Convergence - as an object comes closer our eyes have to come together to keep focused on the object.

  13. Monocular Cues • Monocular cues – depth cues used with oneeye • Used to judge distance of object far away from you • Examples: • Linear Perspective • Interposition • Relative size • Relative height • Texture gradient • Shadowing

  14. Interpositioncloser objects cut off the view of part or all of a more distant one

  15. Relative Sizethe smaller of two objects is perceived as farther away

  16. Relative Heightobjects higher in our field of vision furthest away Horizontal vertical illusion

  17. Linear Perspectiveprovides a cue to distance when parallel lines seem to converge in the distance

  18. Relative Motionobjects beyond the fixation point appear to move with you, objects in front of the fixation point appear to move backward

  19. Light and Shadowbrighter ones seems closer and dimmer one seems further away

  20. Texture Gradientcloser objects have a more distinct texture and farther away objects appear more densely packed and smooth

  21. Which of the following is a binocular cue for the perception of distance? • Interposition • Size Constancy • Linear Perspective • Relative Height • Convergence 0 of 24

  22. Which of the following is most helpful in perceiving the distance of objects far away from you? • Retinal Disparity • Phi phenomenon • Binocular Cues • Continuity • Monocular Cues 0 of 24

  23. Which of the following is a monocular cue? • Retinal Disparity • Perceptual Set • Perceptual Adaptation • Interposition • Convergence 0 of 24

  24. How many monocular cues can you find?

  25. Perceived Motion • Stroboscopic effect – continuous movement in a rapid series of slightly varying images • Example: animated film • Phi phenomenon – an allusion created when two or more adjacent lights blink on and off in quick succession • Example: Blinking Christmas Lights

  26. Constancy • Perpetual constancy – perceiving objects as unchanging even as illumination and retinal images change • Objects change in our retina constantly as we or they move….but we are able to maintain content perception • Examples • Shape Constancy • Size Constancy • Brightness Constancy • Color Constancy

  27. Perceptual Constancy • Shape constancy – perceive objects as having a constant shape

  28. Perceptual Constancy • Shape Constancy illusion– some times we perceive the shape of something to change with the angle of our view

  29. Perceptual Constancy • Size constancy – perceive objects as having a constant size

  30. Perceptual Constancy • Size constancy illusion– sometimes we perceive objects as having a changing size because of the interplay between perceived size and distance • Moon illusion • Ponzo illusion

  31. Ames Room

  32. Ames Room

  33. Lightness Constancy • Lightness constancy aka Brightness constancy – perceiving an object as having constant lightness even while its illumination varies. • Depends on… • Relative luminance – the amount of light an object reflects relative to its surroundings

  34. Color Constancy • Color constancy – familiar objects are perceived to be the same color even if the light they reflect changes. • Depends on what we’re comparing it to… • Surrounding context – perceived color is influenced by its surrounding context • Surrounding objects – perceived color is influenced by its surrounding objects Example: color of these blue circles are identical . Because the brain computes the color of an object relative to its context, the perceived color changes Apple in a bowl of fruit appears to be red even if the light changes because the brain perceives (expects) it to be red.

  35. Light Constancy refers to the fact that • The frequency of light waves has a fixed relationship to the brightness of the light • objects are perceived to have consistent lightness even if the amount of light they reflect changes. • light waves reflected by an object remain constant despite changes in illumination levels. • the perceived whiteness of an object has a constant relation to its lightness. • one of the depth cues involves perceiving dimmer objects as being farther away. 19 of 27

  36. Although the image of a car on our retina becomes smaller as the car moves farther away, we perceive the car to as able to still hold 4 passengers. Which of the following best describes this phenomenon • Perceptual Set • Context Effect • Lightness Constancy • Size Constancy • Context Effects

  37. On a cloudy day, you are likely to perceive a yellow flower as ______________on a clear sunny day • Less colorful than • Less yellow than • Equally as yellow as • More whiter than • More yellow than

  38. Sensory Deprivation and Restored Vision • Experiments on sensory deprivation • Brains cortical cells don’t develop normal connections to interpret visual stimuli • Critical period - specific time during which an organism has to experience stimuli in order to progress through developmental stages properly. • There is a critical period for normal perceptual development

  39. Perceptual Adaptation Perceptual adaptation – the ability to adjust to artificially displaced or inverted visual field • Demonstrates the impact of experience on perception Example: • Displacement goggles

  40. Perceptual Set Perceptual set (aka mental predisposition) – mental predisposition to perceive one thing and not another • Schemas – concepts that organize and interpret unfamiliar info/ambiguous situations Examples: Do we see a saxophonist or woman’s face Do we see a Lochness Monster, or a log Does pilot hear “Cheer up” or “Gear up”

  41. Perceptual Set

  42. Context Effects • Context effects – perceptual set can be influenced by the context (expectations and emotions, and motivations) • Examples: • eel of orange or eel of wagon • Sun Ming 7’9”vs. “little guy” at 6’9”

  43. Humans born blind or kittens raised under restricted conditions do not have the cortical regions needed to interpret visual stimuli. Sensory restriction does not appear to do damage if it occurs later in life. This suggests that • a critical period exists for normal perceptual development. • perceptual adaptation to changed visual input can be dramatic. • a given stimulus may trigger widely different perceptions. • detecting a stimulus depends on the signal's strength and our psychological state. • much of our information processing occurs automatically. 0 of 24

  44. Although Chris sees his teacher in school everyday, he didn’t recognize her when he saw her at Menchies. This best illustrates the importance of • Monocular Cues • Perceptual Set • Context Effects • Proximity • Perceptual Adaptation 0 of 24

  45. The tendency to perceive a moving light in the night sky as belonging to an airplane rather than a satellite best illustrates the impact of • Perceptual Constancy • Relative Height • Context Effects • Perceptual Set • Feature detection