5 Steps to a 5 AP Psychology, 2010-2011 Edition (26 page)

Binocular cues include retinal disparity and convergence. Your principal binocular cue is retinal disparity, which is the slightly different view the two eyes have of the same object because the eyes are a few centimeters apart. You can experience retinal disparity by extending your arm directly in front of you with your thumb up. Close one eye while looking at your thumb with the other. Then close the open eye and open the closed eye. Your thumb appears to move with respect to the background. If you follow the same procedure with your thumb closer, you’ll notice that your thumb appears to move more. The degree of retinal disparity decreases with distance. With both eyes open, your brain fuses the two images, resulting in perception of depth. Convergence is the inward turning of your eyes that occurs when you look at an object that is close to you; the closer an object, the more convergence. You can experience convergence by looking at the tip of your nose with both eyes. Convergence is a less important distance cue than retinal disparity and cannot be used for objects beyond about 8 meters (about 25 feet).

Monocular cues include motion parallax, accommodation, interposition or overlap, relative size, relative clarity, texture gradient, relative height or elevation, linear perspective, and relative brightness. Motion parallax and accommodation require active use of your eye in viewing, whereas the other monocular cues are pictorial depth cues that can be given in a flat picture. Motion parallax involves images of objects at different distances moving across the retina at different rates. Closer objects appear to move more than distant objects when you move your head. When riding in a moving vehicle, you see very close objects move rapidly in the opposite direction; more distant objects move more slowly past you; extremely far away objects, such as the moon, seem to move with you. Accommodation of the lens increases as an object gets closer.

Look outside your window to notice all of the pictorial cues.

• Interposition or overlap can be seen when a closer object cuts off the view of part or all of a more distant one.

• Relative size of familiar objects provides a cue to their distance when the closer of two same-size objects casts a larger image on your retina than the farther one.

• Relative clarity can be seen when closer objects appear sharper than more distant, hazy objects.

• Texture gradient provides a cue to distance when closer objects have a coarser, more distinct texture than far away objects that appear more densely packed or smooth.

• Relative height or elevation can be seen when the objects closest to the horizon appear to be the farthest from you. The lowest objects in our field of vision generally seem the closest.

• Linear perspective provides a cue to distance when parallel lines, such as edges of sidewalks, seem to converge in the distance.

• Relative brightness can be seen when the closer of two identical objects reflects more light to your eyes.

• Optical illusions, such as the Muller-Lyer illusion, and the Ponzo illusion, in which two identical horizontal bars seems to differ in length, may occur because distance cues lead one line to be judged as farther away than the other. Similarly, the moon illusion may occur because the moon when near the horizon is judged to be farther away than when it is high in the sky, although in both positions it casts the same image on the retina.

At the San Francisco Exploratorium website, you can see examples of visual illusions and link to other great sites. Go to
www.exploratorium.org
.

As a car approaches, you know that it’s not growing in size, even though the image it casts on your retina gets larger, because you impose stability on the constantly changing sensations you experience. This phenomenon is called
perceptual constancy
. Three perceptual constancies are size constancy, by which an object appears to stay the same size despite changes in the size of the image it casts on the retina as it moves farther away or closer; shape constancy, by which an object appears to maintain its normal shape regardless of the angle from which it is viewed; and brightness constancy, by which an object maintains a particular level of brightness regardless of the amount of light reflected from it. The real shape, orientation, size, brightness, and color are perceived as remaining relatively constant even when there are significant variations in the image it projects. This enables you to identify objects no matter what your viewing angle is, how far away you are, or how dim the lights are.

Have you ever looked through a periscope or displacement goggles and tried to reach for an object only to find it wasn’t where you thought it was? If you repeated your actions, after a short period of time you were probably able to reach the item easily. You adapted to the changed visual input. Newly sighted people who had been blind from birth are immediately able to distinguish colors and to separate figure from ground, but only gradually become able to visually recognize shapes. Visual perception can also be influenced by cultural factors, assumptions, and beliefs. To make use of the cue of relative size, you need to be familiar with the object and have been exposed to viewing objects in the distance.

Your perceptual set or mental predisposition can influence what you perceive when you look at ambiguous stimuli. Your perceptual set is determined by the schemas you form as a result of your experiences.
Schemas
are concepts or frameworks that organize and interpret information. This can account for people’s interpretations of unidentified flying objects (UFOs), the Loch Ness monster, or seeing a cloud of dust in a movie.

Parapsychologists study evidence for psychological phenomena that are currently inexplicable by science. They try to answer the question “Is there perception without sensation?”
ESP (extrasensory perception)
is the controversial claim that perception can occur apart
from sensory input.
Parapsychology
, the study of paranormal events, investigates claims of ESP, including

• telepathy: mind-to-mind communication;

• clairvoyance: perception of remote events;

• precognition: perception of future events;

• telekinesis or psychokinesis: moving remote objects through mental processes.

In 1998, a National Research Council investigation on ESP concluded that the best available evidence at that time did not support the contention that these phenomena exist.

1
. Mechanical energy of vibrations is transduced to the electrochemical energy of neural impulses at the

(A) retina

(B) lens

(C) cochlea

(D) olfactory mucosa

(E) taste buds

2
. Of the following, which bend incoming light rays to focus an image on the retina?

I. cornea

II. iris

III. lens

(A) I only

(B) II only

(C) III only

(D) I and III only

(E) I, II, III

3
. When food supplies may be unsafe, which of the following would have an adaptive advantage over most other people?

I. Supertasters

II. Average Tasters

III. Nontasters

(A) I only

(B) II only

(C) III only

(D) I and III only

(E) I, II, III

4
. On its way to the cones and rods of the eye, (in order) light passes through the

(A) cornea, vitreous humor, lens, iris, aqueous humor

(B) sclera, lens, pupil, iris, vitreous humor

(C) cornea, aqueous humor, pupil, lens, vitreous humor

(D) sclera, aqueous humor, lens, pupil, vitreous humor

(E) retina, vitreous humor, lens, iris, aqueous humor, fovea

5
. Neural impulses go directly to the cortex without passing through the thalamus from receptors in the

(A) retina

(B) joints

(C) cochlea

(D) olfactory epithelium

(E) taste buds

6
. Of the following, which is not a basic taste?

(A) sweet

(B) salty

(C) peppery

(D) bitter

(E) sour

7
. Receptors for kinesthesis are located in the

(A) retina

(B) joints

(C) semicircular canals

(D) olfactory epithelium

(E) taste buds

8
. Carlos was just able to perceive a difference in weight when Maria removed two of the 50 jelly beans from his plastic bag. It is most likely that if Carlos had the jumbo bag of 100 jelly beans, the smallest number of jelly beans he could notice removed would be

(A) 2

(B) 4

(C) 8

(D) 16

(E) 20

9
. Conventional hearing aids may restore hearing by

(A) restoring functionality to a badly punctured eardrum

(B) amplifying vibrations conducted by facial bones to the cochlea

(C) translating sounds into electrical signals wired into the cochlea’s nerves

(D) stimulating the semicircular canals to transduce sound waves

(E) converting sound waves to radio waves

10
. The theory that best accounts for the experience of pain is

(A) the opponent-process theory

(B) Weber’s law

(C) the trichromatic theory

(D) the direct perception theory

(E) the gate-control theory

11
. Which sense is
least
involved in enabling you to maintain your balance when you stand on one foot?

(A) kinesthesis

(B) olfaction

(C) vision

(D) vestibular sense

(E) somatosensation

12
. Although sound comes from speakers on the sides of the room, viewers watching a movie perceive the sound coming from the screen. This phenomenon is best accounted for by

(A) visual capture

(B) proximity

(C) closure

(D) opponent-processes

(E) feature-detection

13
. Your tendency to see the words “went” and “ties,” rather than the word “twenties” when you look at T WENT TIES is best explained by the organizing principle of

(A) bottom-up processing

(B) closure

(C) continuity

(D) figure–ground

(E) proximity

14
. A landscape painting shows boats on a lake in the foreground and mountains farther away. Of the following, which cue would
not
contribute to your perception that the mountains are farther away than the boats in the picture?

(A) texture gradient

(B) linear perspective

(C) relative height

(D) retinal disparity

(E) interposition

15
. When a fortune teller claims to have the ability to see what the person you will meet and marry 10 years from now will look like, the person is professing to possess the ability of

(A) telepathy

(B) clairvoyance

(C) precognition

(D) telekinesis

(E) top-down processing

1. C—
Hair cells of the cochlea transduce the mechanical energy of sound waves to the electrochemical energy of neural impulses. Rods and cones of the retina transduce light energy; cells of the olfactory epithelium and taste buds transduce chemical energy.

2. D—
The curved transparent cornea and curved lens both bend light rays focusing an image on the retina.

3. A—
Supertasters are especially sensitive to the sensation of bitterness that they dislike intensively and that is characteristic of many poisons. Tasters and nontasters are less sensitive to bitter substances and could die from eating them.

4. C—
Light passes through mainly transparent structures. The iris and sclera are not transparent.

5. D—
Smell is our most direct sense. Neurons from the olfactory mucosa synapse with neurons in the olfactory bulbs of the brain.

6. C—
Peppery is sensed by pain and temperature receptors and is not a basic taste. Other than sweet, salty, bitter, and sour; umami is considered a basic taste by some psychologists.

7. B—
Receptors for your sense of body position are located primarily in joints and tendons. Receptors for your vestibular sense or sense of balance are located in the semicircular canals of the inner ear.

8. B—
According to Weber’s Law, the jnd is proportional to the intensity of the stimulus. So if the strength of the stimulus is doubled, the strength of the change in the stimulus that is just noticed must be doubled also.

9. B—
Conventional hearing aids are primarily amplifiers. Facial bones other than the ossicles can transmit vibrations to the cochlea when vibrations are intense. Choice “C” describes cochlear implants.