proximity

Answer: Figure-ground.

Various illusions demonstrate that figure-ground perception is reversible

under some conditions. The example of the word on a page and the illusions all

strongly suggest that figure-ground perception is a mental construction, not necessarily

a fact about the physical world.

Perception: Why Do Things Look the Way They Do? 59

Max Wertheimer, as you will recall from chapter 1, is the father of Gestalt psychology.

Adding to figure-ground perception, Wertheimer proposed a set of supplemental

inborn organizing tendencies, or Gestalt laws. (The Gestalt laws are

also traditionally called innate tendencies, which simply means "inborn." The

words innate and inborn can be used interchangeably.)

First, proximity refers to the nearness of the elements that make up a perception.

If four ink dots on a piece of paper are arranged in the form of a square,

this Gestalt (i.e., organized whole) will, of course, be perceived to be a square. Let

assume that two figures are drawn. Figure A has dots that are one inch apart. Figure

B has dots that are three inches apart. Figure A will give a stronger impression

of being a square than will Figure B.

When you look at stars in the sky and perceive constellations, it is because of

the law of proximity. The "nearness" of some stars to each other creates clusters

that we can easily imagine to be objects such as a dipper, a hunter, or a lion.

(a) Various illusions demonstrate that figure-ground perception is under

some conditions.

(b) What organizing tendency refers to the nearness of the elements that make up a perception?

Answers: (a) reversible; (b) Proximity.

Second, similarity refers to characteristics that elements have in common.

Let's say that the word airplane is printed on a page in a single color of ink. Imagine

that the same word is printed on a different page with its letters randomly

appearing in black, red, and green. The second word is more difficult to perceive

as a whole word, as a perceptual object, than is the first word. Similarity of the elements

helps to make a perceptual object a coherent whole.

If a moth is dark gray and it lands on a tree with dark gray bark, it will be difficult

to perceive the moth at all. This is because its similarity to the bark makes it,

from a perceptual point of view, a part of the bark. However, if a light gray moth

lands on the same tree, it will be easy to pick the moth out as a figure.

Third, closure is the tendency to fill in gaps in information and make a perceptual

object into a complete whole. Imagine that an arc of 340 degrees is drawn

on a piece of paper. Although at a sensory level this is an arc, you will tend to perceive

it as a broken circle, as a coherent whole with a defect. (An unbroken circle

has 360 degrees.) A newspaper photograph made up of nothing but disconnected

dots is nonetheless perceived as a picture of people or things. Again, the principle

of closure is at work.

Fourth, common fate exists when all of the elements of a perceptual object

move or act together. (Their simultaneous activity is, in a sense, a "common

fate.") When this happens, the perceptual object is quickly organized into a figure

60 PSYCHOLOGY

and is easily discriminated from a ground. For example, a polar bear with white

fur surrounded by snow is more easily seen as a bear when it is moving than when

it is stationary. Other organizing tendencies exist; however, the ones presented

make clear the role that they appear to play in perception.

(a) What organizing tendency refers to characteristics that elements of perception have in

common?

(b) The tendency to fill in gaps in information and make a perceptual object into a complete

whole is called .

Answers: (a) Similarity; (b) closure; (c) move or act together.

Learned Aspects of Perception: Is the Infant's World

a Buzzing, Blooming Confusion?

William James said that the infant's world is "a buzzing, blooming, confusion."

There are flashes of light, noises, pressure on the skin, and so forth. But do they

have any organization? Are patterns perceived? Or is there just a lot of random

sensory activity? One gets the impression from James's comment that the infant,

at least temporarily, inhabits a chaotic psychological world. We have seen from

the exposition of the Gestalt laws that this is probably not completely correct.

Innate organizing tendencies either immediately or very quickly help the infant

to stabilize perceptions and introduce some sort of order into whatever is happening.

Nonetheless, it is important to appreciate that learning also plays a role in perception.

The Gestalt laws may play a primary role, but learning certainly plays a

secondary, and important, role.

Let's say that a simple melody is played on the piano in the presence of

Tina, a two-week-old infant. Assume that Tina has had little or no experience

with hearing music. Does she now actually perceive a melody in somewhat the

same way that you perceive it? Or does she just hear a lot of disconnected

tones? You can put yourself in Tina's position to some extent by imagining

yourself listening to the music of another country, one that uses a tonal scale

and patterns of harmony that are unfamiliar to you. When you first hear a song,

it may seem to have little or no pattern. However, hearing it two or three times

will help you to perceive the pattern. To the extent that you, or Tina, can hear

any pattern at all on the first presentation, it is probably due to the Gestalt laws.

The sharpening of perception on repeated presentations can be attributed to

learning.

Perception: Why Do Things Look the Way They Do? 61

(a) William James's suggestion that the infant's world is a "buzzing, blooming, confusion"

gives the impression that the infant, at least temporarily, inhabits a psychological

world.

(b) The sharpening of a perception on repeated presentations of a stimulus can be attributed

to .

Answers: (a) chaotic; (b) learning.

One way to explain this sharpening of perception is to suggest that patterns of

stimulation set off chain reactions in neurons located, let us say, in the association

areas of the brain's cortex. Each time a given stimulus is presented, the same set of

neurons fire. The research of the Canadian psychologist Donald O. Hebb suggests

that repeated firings form a cell assembly, a stable group of neurons that are used

over and over by the brain to create a representation of the external pattern. A pattern

can, of course, be quite complex. If this is so, a given cell assembly may represent

only a portion of a pattern. Hebb called a set of cell assemblies grouped

together to form a larger pattern a phase sequence.

The existence of cell assemblies helps account for a memory of patterns and

perceptual objects. When you hear a melody or recognize something you have

seen before, it is quite possibly because an established cell assembly is firing.

Learning also plays a role in perception because we are conscious beings who

attach labels to perceptual objects. This brings us to the cognitive hypothesis in

perception, the hypothesis that we not only perceive, but know what we are perceiving.

If you see a friend and think, "There's Erin," or hear a song and think,

"That's 'God Bless America' by Irving Berlin," then you have increased the acuity

of your perceptual world. Cognitive learning, learning in which consciousness

plays an important role, is an important aspect of the perceptual process. There is

more about learning in general and cognitive learning in particular in chapter 6.

(a) According to Hebb, a cell assembly is a stable group of .

(b) The hypothesis that we not only perceive, but know we perceive is called the

Answers: (a) neurons; (b) cognitive hypothesis.

Illusions: What Do They Teach Us about Perception?

An illusion is a false perception, a perception that does not fit an objective

description of a stimulus situation. An illusion is usually associated with a particular

sense. Consequently, there are optical illusions, auditory illusions, and so

forth. Illusions tend to be remarkably stable. They affect most normal observers in

62 PSYCHOLOGY

the same way. For example, for almost all of us the Moon is perceived to be larger

when low and near the horizon than when it is high and overhead.

It is important to distinguish the concept of an illusion from a delusion and a hallucination.

A delusion is a false belief. If Ray, a schizophrenic mental patient,

believes that he has an eye with X-ray vision on the back of his head, this is a delusion.

A hallucination is a perception created by the individual. It has no relationship

to reality at all. If Ray sees and hears an invisible companion that nobody else can see

or hear, this is a hallucination. Illusions are thought to be normal and experienced by

most of us. Delusions and hallucinations are thought to be abnormal and experienced

in an idiosyncratic fashion. (There is more about abnormal behavior in chapter 14.)

(a) An illusion is a .

(b) A delusion is a .

Answers: (a) false perception; (b) false belief; (c) perception.

Illusions teach us that perceptions are, to some extent, created by the brain and nervous

system, that we are not passive observers of our world. Let's return to figureground

perception. We perceive the relationship between a figure and its associated

ground as being a fact about the world itself. But is it? The vase-faces illusion can

be perceived in two different ways. (See the illustration on page 64.) It can be seen as

a vase. Or it can be seen as two profiles facing each other. When seen as a vase, this

becomes figure and tends to stand forward a little in perception. The faces disappear

and become absorbed into a receding ground. When seen as two faces, these become

figure, and both tend to stand forward a little in perception. The vase disappears and

becomes absorbed into a receding ground. These two different perceptual alternations

will take place for most observers on a predictable basis. Also, it is impossible to

simultaneously perceive both organizations. All of this suggests that figure and ground

are organizing tendencies linked to perception, not facts about the external world.

How can the vase-faces illusion be explained? Here is one approach. The vasefaces

drawing is said to be ambiguous, meaning that it can be perceived in more

than one way. The process of attention, characterized by a tendency to focus on

some stimuli and ignore others, determines that one organization will be temporarily

favored over another. Let us say that the first organization favored is the

vase. The region of the brain being stimulated by the vase organization becomes

satiated ("overfilled") with the vase organization. It spontaneously rejects it for a

second organization, one that is briefly refreshing. The satiation hypothesis

suggests that the brain tends to reject excessive stimulation of one kind and tends

to seek novel stimulation of another kind. Ambiguity, attention, and satiation are

factors that all work together to produce the fluctuations in perception that take

place when one experiences the vase-faces illusion.

Perception: Why Do Things Look the Way They Do? 63

(a) Illusions teach us that we are not of our world.

(b) A drawing that can be perceived in more than one way is said to be .

Answers: (a) passive observers; (b) ambiguous.

Returning to the Moon illusion, why does the Moon appear larger on the

horizon than when it's overhead? The illusion is a variation of the Ponzo illusion,

an illusion associated with linear perspective. Parallel lines, like those associated

with railroad tracks or the sides of a roadway, appear to converge as they

approach the horizon. At the horizon itself they meet, and this is called the vanishing

point. If in a drawing two objects of the same size are simultaneously

placed so that the first object is far from the horizon and the second one is near

the horizon, the second object will be perceived as being larger than the first one.

This is because, in a drawing, the retinal size of both objects is the same. However,

the second object seems to be larger than it is in terms of comparisons we automatically

make with other objects near the horizon.

Note that in everyday perception the Ponzo illusion does not occur. This is

because the retinal size of an object near the horizon is smaller than that of an

object closer to you. When the size of an image projected on the retina shrinks

with distance, the apparent size of the object remains the same. This is a perceptual

phenomenon called size constancy. For example, an approaching friend first

seen when twenty feet away and then when closer to you appears to be the same

size. However, in the case of the Moon illusion, the size of the Moon's image pro-

64 PSYCHOLOGY

The vase-faces illusion.

jected on your retina is about the same size when it is near the horizon and when

it's "far" from it (when it's overhead). As the Moon orbits our planet, its actual

distance from the Earth doesn't change significantly. Consequently, the conditions

of the Ponzo illusion are met.

What we learn from illusions is that the world appears to us the way it does

not only because it actually is the way it is. We also interpret sensory information,

transforming it into a constructed perceptual, or psychological, world. And it is

our perception of the world that determines much of our behavior.

(a) The Moon illusion is a variation of the .

(b) An object five feet away may look the same size as an object ten feet away. This is an

example of .

Answers: (a) Ponzo illusion; (b) size constancy.

Depth Perception: Living in a Three-dimensional World

One of the fascinating questions of perception is this one:Why do we perceive a

world of rounded shapes, of near and far things, of depth instead of a flat world

with one surface? A second, related question is: How is this accomplished?

A given eye's retina is basically a surface, not a cube. (Although the eye itself

is a three-dimensional "ball," the surface of the retina is not.) Think of the information

on the surface of the retina as having some similarity to an oil painting

made on a flat canvas. Note that it is possible to perceive depth in a landscape

painting made on a flat canvas.

Depth perception is made possible by various cues, signals or stimuli that provide

an observer with information. Depth perception is made possible by cues

arising from binocular vision and monocular vision.

Binocular vision is vision with two eyes. The principal cue for depth perception

associated with binocular vision is retinal disparity. The pupils of the

eyes are about three inches apart. This gives the right eye a somewhat different

view of a scene than the one obtained with the left eye. Notice that although you

sense two images, you only perceive one. (This is another example of the difference

between sensation and perception.) This is sometimes called the zipper

function of the brain, the capacity of the visual portion of the cortex to integrate

two images into a meaningful whole. The whole image, in part because of retinal

disparity, appears to be three-dimensional.

(a) Binocular vision is vision with .

(b) The principal cue for depth perception arising from binocular vision is .

Answers: (a) two eyes; (b) retinal disparity.

Perception: Why Do Things Look the Way They Do? 65

Monocular vision is vision with one eye. If a person is deprived of binocular

vision, then he or she can still perceive depth with the assistance of monocular

cues. (Although the loss of the use of an eye impairs depth perception, it does not

destroy it completely.) Monocular cues are available to one eye. These are the

kinds of cues that give a landscape painting depth. Although you normally look at

such a painting with both eyes open, in this case depth perception is not arising

because of retinal disparity. Close one eye and look at the painting. The perception

of depth will remain.

A first monocular cue is linear perspective, the tendency of parallel lines to

seem to converge as they approach the horizon. Linear perspective was referred to

earlier in connection with the Moon illusion. A second monocular cue is interposition,

a cue created when one object blocks some portion of another object.

If a person is standing in front of a tree, and the tree is partly blocked, it is easy to

see that the tree is behind, not in front of, the person.

A third monocular cue is shadows. Shadows are differences in illumination

gradients. These tend to help us see rounded surfaces as convex or concave. A

fourth monocular cue is texture gradient. A texture gradient is perceived when

we can see less detail in far away objects than those that are closer to us. Such a

gradient appears spontaneously when we look at a field strewn with rocks.

A fifth monocular cue is motion parallax, the tendency when moving forward

fairly rapidly to perceive differential speeds in objects that are passing by and

in those that are being approached. For example, in a traveling car, nearby telephone

poles approach rapidly and then flash by. Look down the road. The telephone

poles seem to be approaching slowly. If you can see telephone poles very

far away, they seem to be almost stationary.

All of these monocular cues work together to enhance depth perception.

(a) Monocular vision is vision with .

(b) The tendency of parallel lines to seem to converge as they approach the horizon is

called .

Answers: (a) one eye; (b) linear perspective; (c) Motion parallax.

Extrasensory Perception: Is It Real?

The novel Slan by A. E. van Vogt has become a science-fiction classic. First serialized

in the magazine Astounding Science Fiction in 1940, the story relates the adventures of

a boy with telepathic powers and his conflicts with nontelepathic adversaries. Telepathy

has become a staple of science fiction and is taken for granted as a power of the

mind in many novels and films. But is it real?

66 PSYCHOLOGY

Before we address the fact or fiction of telepathy, let's explore the phenomenon

as if it were real. This will permit us to understand more accurately what people

mean when they use words such as telepathy.

Telepathy belongs to a larger category of phenomena called extrasensory

perception. Extrasensory perception, or ESP, is the capacity to be aware of external

events without the use of one of the conventional senses such as vision or hearing.

ESP is referred to as the sixth sense, but as you learned in chapter 4, there are

at least seven readily identified senses. ESP should more accurately be called the

eighth sense.

There are three kinds of extrasensory perception: (1) precognition, (2) telepathy,

and (3) clairvoyance. Precognition is the power to know what will happen

in the future. Living almost five hundred years ago, the French physician and

astrologer Nostradamus is one of the more famous individuals in history purported

to have had precognitive powers.

(a) Identify the three kinds of extrasensory perception.

(b) Precognition is the power to know what will happen in the .

Answers: (a) Precognition, telepathy, and clairvoyance; (b) future.

Telepathy is the power to send and receive mental messages. The ability to

read the minds of people who can't read yours is also considered to be a telepathic

power. A spy with this ability would have a useful psychological tool. In the first

half of the twentieth century Upton Sinclair, author of The Jungle and a defeated

candidate for governor of California, conducted telepathic experiments with his

wife and published a book called Mental Radio.

Clairvoyance is the power to have visions and "see" something out of the

range of normal vision. (The word clairvoyance has French roots meaning "clear

seeing.") Some clairvoyants are asserted to be able to give medical readings and

visualize an illness in another person in the same way that an X-ray machine can.

A person who can combine the two powers of precognition and clairvoyance is

thought to be able to both predict and visualize future events. The term seer

implies an ability to combine these powers.

(a) The power to send and receive mental messages is called .

(b) The word vision is associated with what kind of ESP?

Answers: (a) telepathy; (b) Clairvoyance.

Although not a form of ESP, there is another power often associated with it.

This is psychokinesis or PK. Psychokinesis is the power to move objects using

only energy transmitted by the mind. In the movie The Empire Strikes Back, the

hero Luke Skywalker lifts a small spaceship out of the muck of a bog with PK. A

Perception: Why Do Things Look the Way They Do? 67

gambler who believes in PK believes he can give the dice a mental nudge as

they're rolling and influence the numbers that come up.

All four of the phenomena mentioned above are combined into a general class

of mental abilities called psi powers, powers of the mind that are thought to transcend

the conventional laws of physics and our ordinary understanding of natural

science. Psi powers are sometimes also called "wild talents."

(a) The power to move objects using only the energy of the mind is called .

(b) What kind of powers are called "wild talents" such as ESP and PK?

Answers: (a) psychokinesis (PK); (b) Psi powers.

Do psi powers, ESP and PK, actually exist? If one were to make a decision

on anecdotal evidence alone, then one would accept the reality of these powers.

There are many stories and personal experiences that relate vivid and seemingly

convincing events that tempt skeptical observers to become believers.

However, anecdotes and personal experiences are hardly the stuff of science.

They can't be verified. They are difficult or impossible to replicate. Often the

only witness is one individual. When the number of subjects in a study is only

one, the study has no reliability and can't be generalized. Consequently, wonderful

stories aren't sufficient evidence in favor of the hypothesis that ESP and

PK are real.

On the other hand, experimental science has explored psi powers. Joseph B.

Rhine (1895–1980), working at Duke University, conducted many experiments on

ESP and PK. He called the study of such phenomena parapsychology. Telepathy

experiments were conducted with the aid of a set of twenty-five cards called Zener

cards. There are five symbols and these are each repeated five times. PK experiments

often involved the tossing of dice because probable outcomes could be accurately

stated. Rhine's research favors accepting the hypothesis that psi powers are

real. Others such as Charles T. Tart, using the experimental method, have obtained

results that are similar to Rhine's.

On the other hand, many psychologists remain unconvinced. They point out

that there are flaws in the methodology of the various parapsychological experiments.

Also, it should be noted that such experiments do not consistently support

the reality of psi powers. Skeptics assert that when parapsychological

experiments are well designed and tightly controlled, many of the positive results

fade away.

It is not possible at this time to make a simple statement saying that psychology

either accepts psi abilities as real or rejects them as false. It can be asserted that

many psychologists—perhaps most—are unwilling to accept the reality of these

phenomena. They don't believe that the data are sufficiently convincing.

68 PSYCHOLOGY

(a) Rhine called the study of such phenomena as ESP and PK .

(b) Many psychologists—perhaps most—are to accept the reality of psi

powers.

Answers: (a) parapsychology; (b) unwilling.

SELF-TEST

1. According to Koffka, the actual world "out there," the world as defined by

physics is

a. the phenomenal world

b. the geographical world

c. the psychological world

d. the subjective world

2. The capacity to see a bird in the sky is an example of

a. the Ponzo illusion

b. a cell assembly working

c. a monocular cue

d. figure-ground perception

3. One of the following is not a Gestalt law.

a. Proximity

b. Similarity

c. The cognitive hypothesis

d. Closure

4. What hypothesis states that we not only perceive, but also know what we are

perceiving?

a. The cognitive hypothesis

b. The sensory hypothesis

c. The motor-neuron hypothesis

d. The Wertheimer-Koffka hypothesis

5. An illusion is

a. a false belief

b. a kind of hallucination

c. the same thing as a delusion

d. a false perception

6. The vase-faces drawing is said to be ambiguous, meaning that

a. its borders are fuzzy

b. it can be perceived in more than one way

Perception: Why Do Things Look the Way They Do? 69

c. it can be perceived in one way only

d. it does not meet the criterion of subjectivity

7. The Moon illusion

a. is caused by large changes in the Moon's distance from the Earth

b. provides a good example of size constancy

c. provides a case in which size constancy breaks down

d. violates figure-ground perception

8. The principal depth perception cue associated with binocular vision is

a. linear perspective

b. texture gradient

c. motion parallax

d. retinal disparity

9. One of the following is not a kind of extrasensory perception.

a. Psychokinesis

b. Precognition

c. Telepathy

d. Clairvoyance

10. What is the status of psi powers in psychology as a science?

a. Psi powers are proven facts

b. No one has done experiments on psi powers

c. The reality of psi powers is still open to question

d. Telepathy is real, but clairvoyance is not

ANSWERS TO THE SELF-TEST

1-b 2-d 3-c 4-a 5-d 6-b 7-c 8-d 9-a 10-c

ANSWERS TO THE TRUE-OR-FALSE PREVIEW QUIZ

1. True.

2. False. Figure-ground perception is sometimes unstable and reversible (e.g., the vasefaces

illusion).

3. True.

4. False. For example, learning often sharpens our perception.

5. False. Clairvoyance is the power to "see" something out of the normal range of vision.

Psychokinesis is the power to move objects using only energy transmitted by the mind.

70 PSYCHOLOGY

KEY TERMS

Perception: Why Do Things Look the Way They Do? 71

ambiguous

attention

binocular vision

cell assembly

clairvoyance

closure

cognitive hypothesis

cognitive learning

common fate

delusion

extrasensory perception (ESP)

figure

figure-ground perception

geographical world

Gestalt laws

ground (or background)

hallucination

illusion

innate tendencies

interposition

linear perspective

monocular cues

monocular vision

motion parallax

parapsychology

perception

phase sequence

Ponzo illusion

precognition

proximity

psi powers

psychokinesis (PK)

psychological world

retinal disparity

satiation hypothesis

shadows

similarity

size constancy

telepathy

texture gradient

vanishing point

vase-faces illusion

Zener cards

zipper function

PREVIEW QUIZ

True or False

1. T F Learning is a more or less permanent change in behavior, or a behavioral

tendency, as a result of experience.

2. T F A conditioned reflex is an inborn response pattern.

3. T F Operant behavior is characterized by actions that have no meaning for

an organism, and, consequently, no consequences.

4. T F Observational learning takes place when an individual acquires behavior

by watching the behavior of a second individual.

5. T F There is no such thing as short-term memory.

(Answers can be found on page 88.)

As indicated in the previous chapter, the perceptual world is a world of

objects that form the basis of our organized experience. Consequently, this

organization also provides the first stepping stone for the learning process.

In order to learn it is essential to experience the world "out there" and

respond to it. In this chapter you will find out how we acquire behavioral

patterns through experience.

6Learning: Understanding

Acquired Behavior

Learning: Understanding Acquired Behavior 73

Objectives

After completing this chapter, you will be able to

• describe the principal aspects of the learning process;

• identify basic concepts in classical conditioning;

• explain the process of operant conditioning;

• give an example of the important role that consciousness plays in learning;

• specify the most important aspects of the memory process.

Think of ways to use the word learned in a sentence, using yourself as a subject

of the sentence. Here are some examples collected from psychology students:

"I learned to drive a car."

"I learned quite a bit of Italian when I was stationed in Italy for two years."

"Little by little I have learned to hate my business partner."

"I learned a lot on the streets where I grew up."

"I learned to be a more loving, understanding person after I got married."

"I learned good table manners when I was a child."

"I learned to smoke by hanging out with friends who smoked."

The above examples of the ways students think about the learning process

reveal that learning takes place under many conditions and in many situations.

Although learning takes place in school, it is clear that much—perhaps most—

learning goes on outside of the classroom. Indeed, the learning process affects

almost everything we do.

Learning is a more or less permanent change in behavior, or a behavioral tendency,

as a result of experience. There are several points to be made about this definition.

First, learning is "more or less" permanent. This suggests that although

learning tends to resist change once it is acquired, it sometimes does change.

Learning can be forgotten. Learning is sometimes subject to a process known as

extinction (to be explained later). Also, what has been learned can sometimes be

shaped or modified. So learning is far from permanent.

Second, the term behavioral tendency indicates that learning is sometimes

dormant, that it does not reflect itself in immediate action. This phenomenon is

called latent learning and it too will be discussed later.

Third, note the focus on the word experience in the definition. In order to

learn it is necessary to receive information. This is done through our sense organs.

Imagine an infant born without vision or hearing. It would be terribly difficult for

74 PSYCHOLOGY

that infant to learn and develop normal intelligence. If the infant had no sense of

touch or smell or balance, then learning would be next to impossible.

Learning is a more or less permanent change in behavior, or a behavioral tendency, as a

result of .

Answer: experience.

Classical Conditioning: Responding to Signals

Imagine that you are reading a menu in a restaurant and your mouth begins to

water. Is this an example of classical conditioning? Yes, it is. You were not born

with a tendency to salivate when looking at a menu. This is behavior acquired

through experience, and, consequently, a kind of learning. Salivating to words on

paper is a conditioned reflex.

Classical conditioning was the first kind of learning to be studied experimentally.

The pioneer researcher into classical conditioning was Ivan Pavlov

(1849–1936), a Russian physiologist. Classical conditioning is characterized by

the capacity of a previously neutral stimulus to elicit a reflex. If a dog is trained to

salivate each time that it hears a tone of a specific frequency, then the tone is the

previously neutral stimulus and the act of salivating is the reflex. Pavlov achieved

his results primarily with a number of dogs that were trained to patiently cooperate

with the researcher while being restrained in harnesses in the laboratory.

There are four basic terms, all closely related, that you need to learn as the

foundation stones of your understanding of classical conditioning. These are (1)

the unconditioned stimulus, (2) the conditioned stimulus, (3) the unconditioned

reflex, and (4) the conditioned reflex.

The unconditioned stimulus is a stimulus that has an inborn power to elicit

a reflex. Food in the mouth is such a stimulus. The physiology of the body is such

that when salivary glands are stimulated by food, saliva will flow.

(a) Classical conditioning is characterized by the capacity of a stimulus to

elicit a reflex.

(b) The unconditioned stimulus is a stimulus that has an power to elicit a

reflex.

Answers: (a) previously neutral; (b) inborn.

The conditioned stimulus is created by the learning process. It acquires a

power that is sometimes (not always) similar to that of the unconditioned stimulus.

If a tone precedes food in the mouth a number of times, then the tone may

Learning: Understanding Acquired Behavior 75

acquire the power to elicit saliva. If a dog salivates when it hears a tone, then the

tone is a conditioned stimulus. It can be argued that the dog has associated the

tone with food and that the tone has become a signal conveying the meaning that

food is coming soon. Indeed, this is one of the important meanings that Pavlov

gave to classical conditioning. He thought of conditioned stimuli as signals.

The unconditioned reflex is an inborn response pattern. A dog has an

inborn tendency to salivate when food is placed in its mouth. Salivating under

these conditions is an unconditioned reflex. The word response is sometimes used

in place of the word reflex. This usage, although common, is somewhat imprecise.

A response to a stimulus is a behavior pattern that suggests a higher level of

organization and complexity than that associated with a reflex. Salivating when

reading a menu's description of a hamburger is a reflex. Ordering the item and

asking that the meat be well done is a response.

A conditioned reflex is a learned response pattern. If a dog salivates to a

tone, then the elicited flow of saliva is a conditioned reflex.

(a) What stimulus acquires a power that is sometimes (not always) similar to the unconditioned

stimulus?

(b) The unconditioned reflex is an response pattern.

and than that associated with a reflex.

Answers: (a) The conditioned stimulus; (b) inborn; (c) organization; complexity.

Several important features of classical conditioning should be noted. First, the

word conditioning implies a kind of learning that does not require reflection and

reasoning. The learning takes place primarily through a process of association.

Infants are capable of classical conditioning. If a baby's mouth begins to make

sucking motions when a milk bottle is in view, then the sucking motions are conditioned

reflexes.

Second, as indicated above, classical conditioning is not limited to dogs and

animals. Although Pavlov used dogs as research subjects, the results of his research

can be generalized to human beings.

Third, conditioned reflexes are involuntary. They are outside of the conscious

control of the subject.

There are various behavioral patterns associated with classical conditioning.

Three of these are extinction, stimulus generalization, and discrimination.

Extinction takes place when the conditioned stimulus is presented a number of

times without the unconditioned stimulus. If a conditioned dog is presented with

a tone, it will salivate. However, if the tone is presented without food a sufficient

number of times, the tone will cease to elicit the conditioned reflex. The dog has,

76 PSYCHOLOGY

in effect, unlearned the conditioned reflex. Extinction should not be confused with

forgetting. Extinction is an active process that is designed to eliminate a conditioned

reflex. The process of actively extinguishing a conditioned reflex is taken

advantage of in desensitization therapy (see chapter 15).

(a) The word conditioning implies a kind of learning that does not require

and .

(b) Outside of the conscious control of the subject, conditioned reflexes are said to be

times without the unconditioned stimulus?

Answers: (a) reflection; reasoning; (b) involuntary; (c) Extinction.

Stimulus generalization occurs when a stimulus that is similar to an original

conditioned stimulus elicits a conditioned reflex. For example, let's say that

a dog is trained to salivate to a pitch that is the equivalent of middle C on the

piano. If a pitch the equivalent of D, a note that is close to C, is sounded, the dog

will also salivate. As the pitch goes higher, there may be some salivation. If the

pitch gets high enough, salivation will stop. This is discrimination, the subject's

ability to tell the difference between an original conditioned stimulus and other

stimuli.

In a classical experiment, Rosalie Raynor, an assistant to John B. Watson,

trained a child to be afraid of a white rat. In subsequent testing, the child, known

in the research literature as Little Albert, showed fear reactions (conditioned

reflexes) when he saw a different white rat, a Santa Claus mask (with white fur),

or a rolled-up white terrycloth dishtowel. This research provides an example of

stimulus generalization in a human being.

(a) What phenomenon occurs when a stimulus that is similar to an original conditioned

stimulus elicits a conditioned reflex?

(b) A subject's ability to tell the difference between an original conditioned stimulus and

other stimuli is called .

Answers: (a) Stimulus generalization; (b) discrimination.

Last Chapter Next Chapter