1. Perception Chapter 6

2. Perception
The process of selecting, organizing, and interpreting sensory information, which enables us to recognize meaningful objects and events.

3. Selective Attention
Perceptions about objects change from moment to moment. We can perceive different forms of the Necker cube; however, we can only pay attention to one aspect of the object at a time.
OBJECTIVE 1| Describe the interplay between attention and perception.
Perceptions come to us moment by moment one perception vanishing as the next appears. On the slide we have a Necker Cube, which evokes more than one perception. The circles can be organized into several coherent images, each equally plausible and your mind switches back and forth from one to the next. Even though you can agree that multiple interpretations exist for the picture- your mind can only see one at a time. This serves to indicate an important principal: that our conscious attention is selective.
Selective attention is simply the act of focusing on a particular object for a period of time, while simultaneously ignoring irrelevant information that is also occurring. This occurs on a daily basis and can be seen in how people pay attention to something and how much attention is given at that time. Because it is impossible to give attention to every stimulus in our environment, we use selective attention to select what stimuli are important as events occur. 
Necker Cube

4. Cocktail Party Effect https://youtu.be/iO3jTl0WuS4
You're at a party. Music is playing. Glasses are clinking. Dozens of conversations are driving up the decibel level. Yet amid all those distractions, you can zero in on the one conversation you want to hear.
This ability to hyper-focus on one stream of sound amid a cacophony of others is what researchers call the "cocktail-party effect." Now, scientists at the University of California in San Francisco have pinpointed where that sound-editing process occurs in the brain—in the auditory cortex just behind the ear, not in areas of higher thought.
These findings, underscore why people aren't very good at multitasking—our brains are wired for "selective attention" and can focus on only one thing at a time. That innate ability has helped humans survive in a world buzzing with visual and auditory stimulation. But we keep trying to push the limits with multitasking, sometimes with tragic consequences. Drivers talking on cellphones, for example, are four times as likely to get into traffic accidents as those who aren't.
Many of those accidents are due to "inattentional blindness," in which people can, in effect, turn a blind eye to things they aren't focusing on. Images land on our retinas and are either boosted or played down in the visual cortex before being passed to the brain. It's a push-pull relationship—the more we focus on one thing, the less we can focus on others.

5. Selective Attention: You will watch a video.
There is no talking during or after the video.
If you have seen the video before, please remain quiet.

6. 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.
Inattentional blindness, also known as perceptual blindness, is a psychological lack of attention and is not associated with any vision defects or deficits. It may be further defined as the event in which an individual fails to recognize an unexpected stimulus that is in plain sight, as was demonstrated in the gorilla video.
Daniel Simons, University of Illinois

7. Read the article handout and discuss the following concepts:
What did the article say about the ability to drive and talk at the same time.
What did the article say about listening to audiobooks?
What did the article say about conversing with real people in the car vs. talking to someone on a wireless phone call?

8. Texting and Driving
(10:43)

9. On your own paper answer the following:
What were the four examples of the dangers of texting and driving according to the video?
Which story made the biggest impact on you, and why?
Why might you have forgotten that you were driving while you were texting?
List your views on texting while driving

10. 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.
Other experiments demonstrate people’s lack of ability to notice the happenings in their visual environment. This was depicted in the video we watched a few weeks ago. There is also a term known as change deafness- which is when the person listening to a speaker doesn’t notice when the speaker switches with someone else.
© 1998 Psychonomic Society Inc. Image provided courtesy of Daniel J. Simmons.

11. http://abcnews.go.com/WhatWouldYouDo/video/fall-change-blindness-19922507 (5:17)
(0.58)
Another form of in-attentional blindness is the phenomenon of choice blindness. When asked after the experiment whether, in a “hypothetical experiment” they would notice such as switch, 84% insisted they would. They exhibit a blindness to the phenomenon that the researches called choice blindness, blindness.

12. Perceptual Illusions
Illusions provide good examples in understanding how perception is organized. Studying faulty perception is as important as studying other perceptual phenomena.
OBJECTIVE 2| Explain how illusions help us understand some of the ways we organize stimuli into meaningful perceptions.
Which line is longer?
A to B or B to C, or are they the same?
Most people assume the lines are the same length.
In reality, the line AB is 25% longer than line BC.
Line AB is longer than line BC.

13. Tall Arch
In this picture, the vertical dimension of the arch looks longer than the horizontal dimension. However, both are equal.
This is a picture of the St. Louis Gateway Arch- the worlds largest human made illusion. Is it wider or taller? To most, it appears taller, however it is just as high as it is wide.
Rick Friedman/ Black Star

14. Illusion of a Worm
© 1981, by permission of Christoph Redies and
Lothar Spillmann and Pion Limited, London
When you look at the picture on the right, it may look like there is a worm crawling beneath the black lines, however, in reality it is just the same blue line as the one on the left with black added above and below the blue lines.
The figure on the right gives the illusion of a blue hazy “worm” when it is nothing else but blue lines identical to the figure on the left.

15. Perception Test
(1:49)

16. 3-D Illusion
Reprinted with kind permission of Elsevier Science-NL. Adapted from
Hoffman, D. & Richards, W. Parts of recognition. Cognition, 63, 29-78
The image on this slide shows what looks like a three dimensional object, however we really know that it is a two-dimensional drawing.
It takes a great deal of effort to perceive this figure in two dimensions.

17. Make a 3D Hand
You will need white paper, a pencil and markers.
Directions:
(3:40)

18. Perceptual Organization
When vision competes with our other senses, vision usually wins – a phenomena called visual capture.
How do we form meaningful perceptions from sensory information?
We organize it. Gestalt psychologists showed that a figure formed a “whole” different than its surroundings.
OBJECTIVE 3| Describe Gestalt psychology's contribution to our understanding of perception.
Have you ever noticed how a series of flashing lights often appears to be moving, such as neon signs or strands of Christmas lights? According to Gestalt psychology, this apparent movement happens because our minds fill in missing information. This belief that the whole is greater than the sum of the individual parts led to the discovery of several different phenomena that occur during perception.
Gestalt psychology was founded by German thinkers Max Wertheimer, Wolfgang Kohler and Kurt Koffka and focused on how people interpret the world. The Gestalt perspective formed partially as a response to the structuralism of Wilhelm Wundt, who focused on breaking down mental events and experiences to the smallest elements. Max Wertheimer noted that rapid sequences of perceptual events, such as rows of flashing lights, create the illusion of motion even when there is none. This is known as the phi phenomenon. Motion pictures are based upon this principle, with a series of still images appearing in rapid succession to form a seamless visual experience.

19. Form Perception
Organization of the visual field into objects (figures) that stand out from their surroundings (ground).
OBJECTIVE 4| Explain the figure-ground relationship and identify principles of perceptual grouping in form perception.
Form perception is the recognition of objects in a particular form within a certain environment. An object is perceived by the retina as a two-dimensional image,[1] but the image can vary for the same object in terms of the context with which it is viewed, the apparent size of the object, the angle from which it is viewed, how illuminated it is, as well as where it resides in the field of vision
Time Savings Suggestion, © 2003 Roger Sheperd.

20. Grouping
After distinguishing the figure from the ground, our perception needs to organize the figure into a meaningful form using grouping rules.
Our mind makes sense of the items we see by grouping them together.
Proximity- we do not see 6 lines, we see 3 sets of 2 lines.
Similarity- we group together figures that are similar to each other. We see the triangles and circles as vertical columns of similar shapes, not as horizontal rows of dissimilar shapes.
Continuity- We perceive smooth, continuous patterns rather than discontinuous ones. This pattern could be a series of alternating semicircles, but we perceive it as two continuous lines- one way, one straight.
Connectedness- because they are uniform and linked, we perceive the two dots and the line between them as a single unit.

21. Grouping & Reality
Although grouping principles usually help us construct reality, they may occasionally lead us astray.
When you look at this dog house you probably perceive it as a whole doghouse as a gestalt because it is a whole, though impossible structure. Your brain is imposing this wholeness on the picture.
Seen from a different angle, you see how the illusion is actually constructed.
Both photos by Walter Wick. Reprinted from GAMES
Magazine. .© 1983 PCS Games Limited Partnership

22. Depth Perception
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.
OBJECTIVE 5| Explain the importance of depth perception, and discuss the contribution of visual cliff research to our understanding of this ability.
Two dimensional images fall on our retina, yet we somehow organize three dimensional perceptions. Seeing objects in three dimensions is called depth perception, and it enables us to estimate their distance from us. At a glance, we estimate the distance of an oncoming car or the height of a house. This is partially innate. Researcher Eleanor Gibson and Richard Walk discovered this using a miniature cliff with a drop-off covered by sturdy glass. They wanted to know if toddlers would walk off the edge of the table, or if the toddler would perceive the depth of the drop off and stop.
Innervisions
Visual Cliff

23. https://www.youtube.com/watch?v=3CAZMoxhYnk (2:44)

24. 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.

25. 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.

26. 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.

27. 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.

28. 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.

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

30. 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

31. 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.

32. 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.

33. 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.

34. 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.

35. 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.

36. Perceptual Constancy
Perceiving objects as unchanging even as illumination and retinal images change. Perceptual constancies include constancies of shape and size.
OBJECTIVE 9| Explain the importance of perceptual constancy.
Shape Constancy

37. Stable size perception amid changing size of the stimuli.
Size Constancy
Stable size perception amid changing size of the stimuli.
OBJECTIVE 10| Describe the shape and size constancy, and explain how our expectations about perceived size and distance to some visual illusions.
Size Constancy

38. Size-Distance Relationship
The distant monster (below, left) and the top red bar (below, right) appear bigger because of distance cues.
Alan Choisnet/ The Image Bank
From Shepard, 1990

39. Size-Distance Relationship
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.
Both photos from S. Schwartzenberg/ The Exploratorium

40. The Ames room is designed to demonstrate the size-distance illusion.

41. The color and brightness of square A and B are the same.
Lightness Constancy
OBJECTIVE 11| Discuss lightness constancy and its similarity to color constancy.
Courtesy Edward Adelson
The color and brightness of square A and B are the same.

42. Color Constancy
Perceiving familiar objects as having consistent color even when changing illumination filters the light reflected by the object.
Color Constancy

43. Perceptual Interpretation
Immanuel Kant ( ) maintained that knowledge comes from our inborn ways of organizing sensory experiences.
John Locke ( ) argued that we learn to perceive the world through our experiences.
How important is experience in shaping our
perceptual interpretation?

44. Restored Vision
After cataract surgery, blind adults were able to regain sight. These individuals could differentiate figure and ground relationships, yet they had difficulty distinguishing a circle and a triangle (Von Senden, 1932).
OBJECTIVE 12| Describe the contribution of restored-vision and sensory deprivation research in our understanding of the nature-nurture interplay in our perceptions.

45. Facial Recognition
After blind adults regained sight, they were able to recognize distinct features, but were unable to recognize faces. Normal observers also show difficulty in facial recognition when the lower half of the pictures are changed.
Courtesy of Richard LeGrand

46. Sensory Deprivation
Kittens raised without exposure to horizontal lines later had difficulty perceiving horizontal bars.
Blakemore & Cooper (1970)

47. Perceptual Adaptation
Visual ability to adjust to an artificially displaced visual field, e.g., prism glasses.
OBJECTIVE 13| Explain how the research on distorting goggles increases our understanding of the adaptability of perception.
Courtesy of Hubert Dolezal

48. Perceptual Set
A mental predisposition to perceive one thing and not another. What you see in the center picture is influenced by flanking pictures.
OBJECTIVE 14| Define perceptual set, and explain how it influences what we do or do not perceive. Right half the class should close their eyes and the left half of the class should see the saxophonist for about 20 seconds. Then the left half of the class should close the eyes and the right half should see the woman’s face. All of them should then write their responses while watching the middle picture. Responses are compared to show perceptual set.
From Shepard, 1990.

49. Perceptual Set Other examples of perceptual set.
Frank Searle, photo Adams/ Corbis-Sygma
Dick Ruhl
(a) Loch ness monster or a tree trunk; (b) Flying saucers or clouds?

50. Schemas
Schemas are concepts that organize and interpret unfamiliar information.
Courtesy of Anna Elizabeth Voskuil
All what we perceive not only comes from the environment but also from our minds. Schemas or concepts develop through experience.
Children's schemas represent reality as well as their abilities to represent what they see.

51. Face schemas are accentuated by specific features on the face.
Features on a Face
Face schemas are accentuated by specific features on the face.
Kieran Lee/ FaceLab, Department of Psychology,
University of Western Australia
Students recognized a caricature of Arnold Schwarzenegger faster than his actual photo.

52. Eyes and mouth play a dominant role in face recognition.
Eye & Mouth
Eyes and mouth play a dominant role in face recognition.
Portrait artists understood the importance of this recognition and therefore centered an eye in their paintings.
Courtesy of Christopher Tyler

53. Context Effects Context can radically alter perception.
OBJECTIVE 15| Explain why the same stimulus can evoke different perceptions in different contexts.
Is the “magician cabinet” on the floor or hanging from the ceiling?

54. Context instilled by culture also alters perception.
Cultural Context
Context instilled by culture also alters perception.
To an East African, the woman sitting is balancing a metal box on her head, while the family is sitting under a tree.

55. Is perception innate or acquired?
Perception Revisited
Is perception innate or acquired?

56. Perception & Human Factors
Human Factor Psychologists design machines that assist our natural perceptions.
OBJECTIVE 16| Describe the role human factors psychologists play in creating user-friendly machines and work settings.
Photodisc/ Punchstock
Courtesy of General Electric
The knobs for the stove burners on the right are easier to understand than those on the left.

57. Human Factors & Misperceptions
Understanding human factors enables us to design equipment to prevent disasters.
Two-thirds of airline crashes caused by human error are largely due to errors of perception.

58. Human Factors in Space
To combat conditions of monotony, stress, and weightlessness when traveling to Mars, NASA engages Human Factor Psychologists.
Transit Habituation (Transhab), NASA

59. Is There Extrasensory Perception?
Perception without sensory input is called extrasensory perception (ESP). A large percentage of scientists do not believe in ESP.
(2:38)
OBJECTIVE 17| Identify the three most testable forms of ESP, and explain why most research psychologists remain, skeptical of ESP.

60. Claims of ESP
Paranormal phenomena include astrological predictions, psychic healing, communication with the dead, and out-of-body experiences, but most relevant are telepathy, clairvoyance, and precognition.

61. Claims of ESP
Telepathy: Mind-to-mind communication. One person sending thoughts and the other receiving them.
Clairvoyance: Perception of remote events, such as sensing a friend’s house on fire.
Precognition: Perceiving future events, such as a political leader’s death.

62. Premonitions or Pretensions?
Can psychics see the future? Can psychics aid police in identifying locations of dead bodies? What about psychic predictions of the famous Nostradamus?
The answers to these questions are NO! Nostradamus’ predictions are “retrofitted” to events that took place after his predictions.

63. Putting ESP to Experimental Test
In an experiment with 28,000 individuals, Wiseman attempted to prove whether or not one can psychically influence or predict a coin toss. People were able to correctly influence or predict a coin toss 49.8% of the time.