1. 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.
With both eyes open, hold up two pens or pencils in front of you and touch their tips together. Now do so with one eye closed. With one eye the task becomes noticeably more difficult, demonstrating the importance of binocular cues in judging the distance of nearby objects. Two eyes are better than one.
Because your eyes are about 2 ½ inches apart, our retinas receive slightly different information. When the brain compares these two images, the difference between them, which is called their retinal disparity, provides important cues to the relative distance of the objects.
Try this: hold up your fingers directly in front of your nose and bring them slowly together. Because your retinas receive very different information, there begins to appear to be an additional finger tip. At a greater distance the disparity between your eyes becomes less pronounced.
The creation of 3D movies comes from following a similar setup to our eyes. Two cameras are placed a few inches apart to record footage. We wear glasses which allow the left eye to only see what the left camera shot, and the right eye to only see what the right camera shot, and creates a 3D image, similar to the way our eyes work when we view the extra finger tip.

2. 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.
Another binocular cue is the concept of convergence. Convergence is due to our eyes being turned lightly inward as things get closer. You brain assess the amount of inward turn to assess the closeness of an object.

3. 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.
In order to determine depth, we use what are called monocular cues. One such monocular cue is the relative size of items. For example, if you are walking along, and you see someone as tiny, you automatically make a determination on how far away they are from you. Your determination can be skewed however if the person is sub-average height.

4. Monocular Cues
Interposition: Objects that occlude (block) other objects tend to be perceived as closer.
Another monocular cue is interposition. Interposition is when we perceive something as being close based on its location of surrounding imagery. Consider this photo- it is difficult to make as assessment about the image because there is confusion between the figure (the horse) and the info we would typically use to ground the image (such as the trees).
Rene Magritte, The Blank Signature, oil on canvas,
National Gallery of Art, Washington. Collection of
Mr. and Mrs. Paul Mellon. Photo by Richard Carafelli.

5. 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.
Another monocular Cue is known as relative clarity. If something appears hazy, it seems further away then when it is a sharp, clear object. This is why it is difficult to assess depth when it is foggy or snowy.

6. Monocular Cues
Texture Gradient: Indistinct (fine) texture signals an increasing distance.
A gradual change from a coarse, distinct texture, to a fine, indistinct texture signals that the object is further away. This monocular cue is known as a texture gradient cue.
© Eric Lessing/ Art Resource, NY

7. Monocular Cues
Relative Height: We perceive objects that are higher in our field of vision to be farther away than those that are lower.
The relative height of images is another monocular cue. This is when we perceive objects higher in our visual field as being further away. This concept may help contribute to the illusion that vertical dimensions are longer than horizontal ones, even if they are actually the same length. (Consider the St. Louis Arch from the other day). This is the same reason that people think that tall thin glasses contain more liquid than a short wide glass.
Image courtesy of Shaun P. Vecera, Ph. D.,
adapted from stimuli that appered in Vecrera et al., 2002

8. 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.
Another monocular cue is Relative motion. When you fix you eyes on a specific object, the items that are closer than the fixed object appear to be moving backwards. For example, if you are riding on a bus, and you look out the window at a house, the house appears to be moving in the same direction you are driving. However, the items closer to you than the fixation point appear to be moving backwards.

9. 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.
Linear perspective is when parallel lines, such as railroad tracts, appear to converge with distance. The more the lines converge, the greater the perceived distance.
© The New Yorker Collection, 2002, Jack Ziegler
from cartoonbank.com. All rights reserved.

10. Monocular Cues
Light and shadow is an additional form of perspective. Nearby objects reflect more light to our eyes. Given the identical objects, the dimmer ones seems further away. This illusion can contribute to accidents when there is fog, and vehicles seem further away then they are. When we look at the pictures on the slide, we see the images on the left as sticking out, while the images on the right look like they sink in. The reason for this is because as people who live on earth, we are used to light coming from above. Thus, there appears to be a shadow on the top creating an illusion of inward depth, as opposed to the pictures on the left which appears to have a shadow on the bottom, making it look like it sticks out.

11. 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.
Motion is a perceptual attribute: the visual system infers motion from the changing pattern of light in the retinal image.
Researcher Nakayama (1985) suggests seven possible reasons why movement perception is important. These are:  to enable us to derive the third dimension
calculate time to collision
distinguish figure from ground
ascertain information about our own movement
stimulate eye movements
understand pattern
perceive moving objects

12. https://youtu.be/0JVJsPpg1-8
If you look at a waterfall for about 30 seconds, and then shift your gaze to a nearby stationary object, such as a rock or a tree, that object will seem to drift slowly upwards. This well known optical illusion demonstrates a phenomenon called the motion after-effect, which is thought to occur as a result of adaptation – the brain compensates for movement in one direction, causing us to momentarily perceive a stationary objects to be moving in the other.

14. Physiological illusions, such as the afterimages following bright lights, or adapting stimuli of excessively longer alternating patterns (contingent perceptual aftereffect), are presumed to be the effects on the eyes or brain of excessive stimulation or interaction with contextual or competing stimuli of a specific type—brightness, colour, position, tile, size, movement, etc. The theory is that a stimulus follows its individual dedicated neural path in the early stages of visual processing, and that intense or repetitive activity in that or interaction with active adjoining channels cause a physiological imbalance that alters perception

15. 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.

16. Perceptual Constancy
Perceiving objects as unchanging even as illumination and retinal images change. Perceptual constancies include constancies of shape and size.
Perceptual constancy enables us to perceive an object as unchanging despite a changing stimulus. For example, despite the fact that this door appears in different angles, we know that it is a door. Due to op-down processing, we can identify things regardless of the angle, distance, and illumination by which we view them. This is a learned process, as is evidenced by the story of the man who had been given eye surgery, making it possible for him to see, resulting in him not recognizing his dog when it was viewed from a different angle, or when he tried to step over his shadow.
The ability to process this information is instantaneous, and is due to the work of millions of neurons working quickly to provide you with necessary information.
Shape Constancy

17. Stable size perception amid changing size of the stimuli.
Size Constancy
Stable size perception amid changing size of the stimuli.
Size constancy is what enables us to know that a car doesn’t actually shrink in size just because it is far away from us. We look at the smaller car on the right and assume that it is the same time as the car on the left, just further away based on its location on the screen. For example, our mind does not look at it, and assume it is a smaller floating car, it assumes it is the same size car at a farther distance.
Size Constancy

18. Size-Distance Relationship
The distant monster (below, left) and the top red bar (below, right) appear bigger because of distance cues.
Given an objects perceived distance and the size of its image on our retinas, we instantly and unconsciously infer the objects size. Although the monsters in this picture are not the same size, we see the one in the back as being much bigger, due to the linear perspective of the landscape around the monster.

19. 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.
The interplay between perceived size and perceived distance helps explain several well known illusions. For example, have you ever noticed how much bigger the moon looks when it is rising, as opposed to when it is in the sky?
Both photos from S. Schwartzenberg/ The Exploratorium

20. The size-distance relationship helps us understand how easily we can be tricked by prior knowledge when determining size. For example, the image depicted here play on our knowledge of the height of ceilings. The red line in the back of the picture is close to the top of the ceiling, and the red line in front of the window is well below the ceiling which suggests it is smaller. In addition, the lines face in such a way as to suggest something about their size as well. The lines that open out (as those in the picture towards the back) suggest that it is a bigger line, as compared to the lines that face inward, making the line look smaller. Actually both lines are the same size.
This perception, like most others is based on experience. In communities (like those in South America where the buildings are round) the people shown these illusion images were not susceptible to it in the same way we typically are.

21. The color and brightness of square A and B are the same.
Lightness Constancy
White paper reflects 90 percent of the light falling on it; black paper, only 10 %. In sunlight a black paper may reflect 100 times more light than does a white paper viewed indoors, yet it still looks black. This illustrates lightness constancy; we perceive an object having a constant lightness even while its illumination varies. Perceived lightness depends on relative luminance- the amount of light an object reflects relative to its surroundings.
Courtesy Edward Adelson
The color and brightness of square A and B are the same.

22. Color Constancy
Perceiving familiar objects as having consistent color even when changing illumination filters the light reflected by the object.
Color constancy is when we can look at an object, and know its color, despite changing light. For example, if we walk into a well lit room and see a bowl of apples, we will know hat they are still green, even if the light changes.
Color Constancy

23. 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.
Philosophers have debated whether our perceptual ability should be credited to our nature or our nurture. To what extent do we learn to perceive? Immanual Kant maintained that knowledge comes from our inborn ways of organizing ways of organizing sensory experiences. Indeed we come to process sensory information.
John Locke argued that through our experiences we also learn to perceive the world. Indeed, we learn to link an object’s distance with it’s size. So, just how important is experience? How radically does it shape our perceptual interpretations.
How important is experience in shaping our
perceptual interpretation?

24. 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).
When asked if a man who was born blind and was now an adult, who had been taught through touch to distinguish between a cube and a sphere could, upon being made to see, visually distinguish between the two. Locke’s answer would have been no, because the man would never have learned to see the difference.
This opinion was put to the test when patients were put under surgery to remove in-born cataracts. They were able to distinguish color, and figure from ground. This suggests that these skills are inborn. As Locke had supposed, the formerly blind patients often could not recognize by sight objects that were familiar by touch.

25. 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.
As we have talked about before, we perceive faces as a whole. If you take the same top half of a picture, and change the bottom half to be two different faces, the two top halves appear differently.
People who have been deprived of visual experience during infancy surpass the rest of us at recognizing that the top halves are the same because they didn’t learn to process faces as a whole. For example, one 43 year old man whose sight was restored after 40 years of blindness, could associate people with distinct features (for example- he knew that Mary was the one with the red hair) but could not instantly recognize a face. He also lacked perceptual constancy: as people walk away from him, they seem to be shrinking in size. Vision- as illustrated in this case, is partly an acquired sense.
Courtesy of Richard LeGrand

26. Sensory Deprivation
Kittens raised without exposure to horizontal lines later had difficulty perceiving horizontal bars.
Researchers conducted experience in which they outfitted them with goggles through which the animals could only see only diffuse un-patterned light. After infancy, they removed the goggles and the kittens displayed perceptual limitations much like those of humans born with cataracts. They could distinguish between color and brightness, but not the form of a circle vs. a square. Their eyes had not degenerated; their retinas still relayed signals to their visual cortex. But lacking stimulation, the cortical cells had not developed normal connections. Thus the animals remained functionally blind to shape.
Blakemore & Cooper (1970)

27. Perceptual Adaptation
Visual ability to adjust to an artificially displaced visual field, e.g., prism glasses.
Given a new pair of glasses, we may feel slightly disoriented, even dizzy. Within a day or two, we adjust. Our perceptual adaptation to changed visual input makes the world seem normal again. But imagine a far more dramatic new pair of glasses- one that shifts the apparent location of objects 40 degrees to the left. When you first put them on and toss the ball to a friend, it sails off to the left. Walking forward to shake hands with the person, you veer to the left.
Can we adapt to this change in perception? Baby chicks cannot. Researchers fit baby chicks with an apparatus to confuse their perception and the birds did not adapt. People on the other hand can adapt fairly quickly. When wearing perception distorting glasses, people can adapt within a few minutes. Once they take the glasses off, their perception is still messed up, overthrowing in the opposite direction , this time throwing too far to the right, but again, you would correct the error fairly quickly.
Even if you wear glasses that flip an image to where you see upside down, your mind can still adapt to the world.
Psychologist George Stratton experienced this when he created headgear that flipped the world upside down. He wore them for eight days. At first, he felt very disoriented. When he wanted to walk, he found himself searching for his feet (because they were now up). Eating was nearly impossible, he became nauseated and depressed. But Stranton persisted and by the eighth day he could comfortably reach for things and walk without bumping into things. Once he removed the headgear, he readapted quickly. Additional experiments showed that people were able to ride a motorcycle, ski the Alps, and fly an airplane. They didn’t adjust in that they saw the world correctly again, they adjusted in that they learned to coordinate their movements in spite of the upside down world.
Courtesy of Hubert Dolezal

28. Perceptual Set
A mental predisposition to perceive one thing and not another. What you see in the center picture is influenced by flanking pictures.
What defines our perceptual set? Through experience we form concepts, or schemas, that organizes and interpret unfamiliar information.
From Shepard, 1990.

29. Perceptual Set Other examples of perceptual set.
Frank Searle, photo Adams/ Corbis-Sygma
Our preexisting schemas for male saxophonists and women's faces, for monsters and tree trunks, for airplane lights and UFO’s all influence how we interpret ambiguous sensations with top-down processing.
Dick Ruhl
(a) Loch ness monster or a tree trunk; (b) Flying saucers or clouds?

30. 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.
A preschooler can draw circles and angled lines but cannot combine them to create an elaborate human figure. The child’s difficulty is not clumsiness. A child's inabilities is in the challenge for the child to represent visually what they see. The main difference however lies in the child’s simplified schema for essential human characteristics. For example, a 3 to 4 year old, a face is more important that a body. This picture depicts the importance of face for the 4 year old who drew it.
Children's schemas represent reality as well as their abilities to represent what they see.

31. 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
Researchers showed how attuned we are to specific facial features. Studies were conducted which asses students from Austria on their abilities to discern the likeliness to identify Arnold Schwarzenegger. They quickly flashed 3 separate images of Arnold, one with anti-characteristics, his actual picture, and a caricaturized image. Students were significantly more likely to recognize the characterized images because we are attuned to noticing them.
Students recognized a caricature of Arnold Schwarzenegger faster than his actual photo.

32. Eyes and mouth play a dominant role in face recognition.
Eye & Mouth
Eyes and mouth play a dominant role in face recognition.
Our face recognition is especially attuned to the expressions of eyes and mouth. Portrait artists understood the importance of this recognition and therefore centered an eye in their paintings.
Courtesy of Christopher Tyler

33. Context can radically alter perception.
Context Effects
Context can radically alter perception.
The Context Effect is a part of Cognitive Psychology that states that the context (environmental factors) that surrounds an event effects how an event is perceived and remembered.
For example, in the image on the powerpoint says read. We know this despite the fact that some of the word is missing.
This effect, that is largely used in the science of marketing, holds that an event is more favorably perceived and remembered when the surrounding environment is comfortable and appealing.  For example, when a person goes shopping or eats out, they are much more likely to spend time in a comfortable and appealing environment thereby increasing the likelihood of making purchases and returning to shop or eat there again.
Other examples include understanding that someone is having a bad day, as opposed to being mean, determining a baby’s gender based on what the baby is wearing, or referees being extra hard on a particular team who is known as being aggressive.

34. Is perception innate or acquired?
Perception Revisited
Is perception innate or acquired?
Is perception innate or learned? We can answer: it’s both. Perception is influenced by both sensation and cognition.

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

36. 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.

37. 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.

38. 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.

39. 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.