CHAPTER
6
PSYCH 100
LEARNING
Background
• Behavioral and Social Learning Theories:
Behaviorism (ch. 1)
• Learning is “the relatively permanent
change in behavior brought about as a
result of experience or practice”
• Learning is an internal event, but learning is not
recognized as learning until it is displayed by
overt behavior
Classical
Conditioning:
Learning Through
Association
Ivan Pavlov
Ivan Pavlov was a
prominent Russian
physiologist who did
research on digestion.
Pavlov discovered
that dogs will salivate
in response to the
sound of a tone in a
process we now call
classical conditioning.
• Classical conditioning is the
process of learning by which a
previously neutral stimulus
comes to elicit a response
identical or similar to one that
was originally elicited by
another stimulus as the result
of the pairing or association of
the two stimuli.
Classical Conditioning
• Simple/Reflex Behavior
• Focuses on ANTECEDENTS: Events
that take place BEFORE the response
• Learning takes place when an
association is made between two
previously unrelated stimuli
Stimulus
à
Response
Stimulus
à
Response
Pavlov’s Demo
Pavlov noticed that the dogs in his experiments salivated
before being fed, whenever they heard the clanging of the
metal food carts being wheeled into the laboratory. To isolate
the cause, Pavlov paired the sound of a bell tone with the
presentation of meat powder several times, then presented
the sound of the tone alone (without meat powder).
Pavlov’s Demo
The dog reacted to the sound of the tone even
without the presentation of meat powder. Pavlov
demonstrated that a learned association was
formed by the pairing of events (tone and meat
powder) in the animal’s environment.
Pavlov’s Demo
(NS)
Neutral Stimulus
(NR)
No Response
At first, the bell tone is a neutral stimulus
that does not cause the dog to drool.
Pavlov’s Demo
(UCS)
Unconditioned
Stimulus
(UCR)
Unconditioned
Response
The meat powder is an unconditioned stimulus that
elicits the unconditioned response. Unconditioned
means unlearned. Dogs naturally salivate around food.
Pavlov’s Demo
Repeated
pairings
(NS)
Neutral
Stimulus
(UCS)
Unconditioned
Stimulus
(UCR)
(NR)
Unconditioned
NoResponse
response
When the neutral stimulus (bell) is paired with the
presentation of meat powder, the unconditioned
response to the meat powder causes the dog to
drool. The neutral stimulus has no effect.
Pavlov’s Demo
(CS)
Conditioned
Stimulus
(CR)
Conditioned
Response
After conditioning (repeated pairing of neutral stimulus
with unconditioned stimulus), the neutral stimulus
becomes a conditioned stimulus, which means that the
bell alone now elicits the response of salivation as the
result of learning by association.
Phase 1: Before Conditioning
(a)
(b)
US (food in mouth)
UR (salivation)
NS (tone)
(no salivation)
Phase 2: During Conditioning
(c)
NS (tone)
+
US (food in mouth)
UR (salivation)
Phase 3: After Conditioning
(d)
CS (tone)
CR (salivation)
Extinction
Extinction
(CS alone)
15
10
5
0
Extinction is the process where the association
between the unconditioned stimulus (meat powder)
and conditioned stimulus (bell ringing) is broken.
When the bell is presented enough times without
being paired with meat, the response extinguishes.
Spontaneous Recovery
Spontaneous
Extinction
Recovery
(CS alone)
15
10
5
24-hour
rest
0
Spontaneous recovery is where the conditioned stimulus
suddenly elicits an extinguished conditioned response when it
is presented again after a period of time after extinction occurs.
Once the CS response had undergone extinction, then after a
24-hr rest period, spontaneous recovery occurs and the
response is back, but not at full strength.
Stimulus generalization is the tendency to for stimuli that
are similar to the conditioned stimulus to elicit the
conditioned response.
Stimulus discrimination is the ability to differentiate
conditioned responses to different but related stimuli.
Factors that strengthen
classical conditioning
include:
1. Frequency of pairings
2. Timing
3. Intensity of the
unconditioned stimulus
Little
Albert
John Watson and Rosalie Rayner, applied principles of
classical conditioning to create a fear response in a young
boy, called “Little Albert.” Albert developed a conditioned
emotional response to fear a white rat through repeated
pairing of the rat with an unpleasant jarring sound. Watson
and Rayner then examined the generalization of the
acquired fear to other related stimuli, such as other furry
objects, including a rabbit, a fur coat, and even Watson
himself wearing a Santa Claus mask.
(CS)
White Rat
(US)
Loud Gong
(CR)
(UR)
Fear
• In the famous case of Little Albert, the CS was
the white rat and the US was the loud gong
sound. The CR to the white rat was a learned
fear response.
• While this project taught us quite a bit, one
must consider the ethical failures of Watson
and Rayner’s work.
• Do you think the results were worth the ethical
violations? Would such a project be permitted
today?
Unconditioned
Stimulus
(Illness)
(CR)
(UR)
Nausea
Conditioned Stimulus
(Taste of Poisoned Berries)
Taste aversion is a special instance of conditioning because
it breaks two of the cardinal rules of the process—it may
occur after only one pairing of CS-US, and the presentation
of the US (illness) and CS (taste) may be separated by hours.
Taste aversion also shows the adaptive value of
conditioning. It is a crucial response that allows us to learn
to avoid certain foods that have sickened us in the past.
Classical Conditioning in the
Real World
1. Advertising
2. Positive
Emotions
3. Drug Cravings
4. Taste Aversions
Operant Conditioning:
Learning Through
Consequences
Operant Conditioning
• A second form of learning is
operant conditioning, learning
from consequences (responses)
that produce changes in behavior
or the environment.
• The major figure in operant
conditioning was the American
psychologist B. F. Skinner.
Operant Conditioning
• A response that is followed by a
reinforcer is strengthened & is more
likely to occur again
• Reinforcer increases the frequency
of a response it follows
• Sequence:
Response à Stimulus (Reinforcer)
Operant Conditioning
• Complex/Voluntary Behavior
• Focuses On CONSEQUENCES: Events
which take place AFTER the target
response
• Learning takes place when a desired
(target) response is affected by its
consequences
• Shaping: A procedure for teaching complex
behaviors that at first reinforces similar
behaviors to the target behavior
EXAMPLES
• Child does homework à gets to play
game
• Child doesn’t do homework à no game
• As children grow, schools expect them to
sit for longer and longer periods of time
• Teacher using drafts to teach writing
1st à basic formatting
2nd à content in right place
3rd à improve quality of content
Edward Thorndike
Based on his use of
a puzzle box in
animal
experiments,
Edward Thorndike,
(an early learning
theorist), proposed
the Law of Effect,
which emphasized
the role of
consequences in
shaping behavior.
B.F. Skinner
Operant conditioning is a
form of learning in which
responses come to be
strengthened by their
consequences. B. F.
Skinner of Harvard
University first described
this type of learning in
the late 1930s.
A Skinner box is a
small enclosure in
which an animal can
be reinforced, with a
food pellet, for a
particular response,
such as pressing a
lever. The rate of
response is recorded.
In the Skinner box,
the floor is electrified
to investigate escape
or avoidance
learning.
Speaker
Signal lights
Lever
To food dispenser
Food pellet
Electric grid
To shock generator
Skinner Box
Operant Conditioning
• Skinner’s principle of reinforcement holds that
organisms tend to repeat those responses that are
followed by favorable consequences, or
reinforcement.
• Something is positively reinforcing if the rate or
probability of a response increases after it is
presented, such as in the case of food, water,
sleep, etc.
• An example of positive reinforcement is when you
tell a joke and all your friends laugh. You then
become more likely to keep telling jokes. But what
happens to the likelihood of your joke telling if no
one laughs?
Operant Conditioning
Behavior
Consequence
Response
Rewarding
Stimulus Presented
Patronize
Diner
Tendency to tell
jokes increases
Behavior
Response
Press lever
Consequence
Tendency to press
lever increases
Rewarding Stimulus Presented
Food delivered
Responses can be strengthened either by presenting
positive reinforcers or by removing negative
reinforcers.
Positive reinforcement occurs when a response is
strengthened when it is followed by the presentation
of a (rewarding) stimulus.
Behavior
Response
Press lever
Consequence
Tendency to press
lever increases
Aversive Stimulus Removed
Shock turned off
A stimulus is negatively reinforcing when its removal
strengthens the preceding response. Negative reinforcers
are aversive stimuli, such as pain or anxiety. The rat in this
example presses the lever, which removes the aversive
effects of an electric shock. A person learns to turn on a fan
or an air-conditioner when these responses are reinforced
by relief from uncomfortable heat.
Primary
Reinforcer
Secondary
Reinforcer
$
• Primary reinforcers – satisfy basic
biological needs or drives
• Secondary reinforcers – acquire their
value through learning and association
with a primary reinforcer
Discriminative Stimulus
Water
Light
Glass
Food pellet
dispenser
Food tray
Lever
When the light shines (a discriminative
stimulus), the food dispenser will release a food
pellet when the animal performs the desired
response (pressing the lever).
Shaping
Operant conditioning is usually
established through a gradual process
called shaping, which involves the
reinforcement of closer and closer
approximations to a desired response.
Shaping is necessary when an organism does not, on
its own, offer the desired response. For example,
when a rat is first placed in a Skinner box, it may not
press the lever at all. In this case the experimenter
begins shaping lever-pressing behavior by reinforcing
(feeding) the rat for successive steps toward the target
response, such as when it moves closer to the lever.
Extinction
Extinction in operant conditioning is the
process by which the association
between response and reinforcer is
broken. The most efficient means of
unpairing a response and a reinforcer is
to stop reinforcing the operant response;
that is, to not present food when the bar
is pressed, for example.
A schedule of reinforcement determines the
occurrences of a specific response result in
presentation of a reinforcer. Continuous
reinforcement occurs when every instance of a
designated response is reinforced. Partial
reinforcement occurs when a designated response is
reinforced only some of the time.
Cumulative Responses
A fixed-ratio schedule entails giving a
reinforcer after a fixed number of desired
responses are produced.
A fixed-ratio schedule generally provides a
rapid rate of response, indicated by the
steep slope of the curve.
Fixed-ratio (FR)
Lower resistance
to extinction
Rapid responding
Short pause after
reinforcement
Time
Cumulative Responses
A variable ratio schedule entails giving a reinforcer
after a desired response occurs following a variable
number of non-reinforced responses. Variable-ratio
schedules, like fixed-ratio schedules, tend to
produce a rapid response rate. Intermittent
reinforcement, or partial reinforcement, occurs
when a designated response is reinforced only some
of the time.
Variable-ratio (VR)
Higher resistance
to extinction High, steady rate
without pauses
Note:
Time
Higher ratios generate
higher response rates
Avoidance Learning
Avoidance behavior is conditioned by presenting a
stimulus, usually a light or bell, that signals that the
aversive stimulus (electric shock) will follow in a few
seconds. The animal learns to avoid the aversive
stimulus by moving to the adjoining (non-electrified)
compartment when the light appears, but before the
painful stimulus is presented.
Punishment
Type of
Punishment
Behavior
Presentation
You bite into a
of unpleasant
hot red pepper
stimulus
Removal of Child hits another
reinforcing child in the
stimulus playground
Punishment
Effect: Frequency
of Behavior Declines
Your tongue burns
You avoid biting hot
peppers in the future
Child is removed from
the playground or is
required to sit out for
a period of time
Child no longer hits
other children in
the playground
Punishment involves the presentation of an aversive
or unpleasant stimulus, or removal of a reinforcing
stimulus, after an undesired response occurs.
Punishment generally leads to a decline in the
frequency of the punished response.
Drawbacks of punishment
• May temporarily suppress but not eliminate
behaviors
• Does not teach new behaviors
• Can have undesirable consequences
• May become abusive
• May represent inappropriate modeling
Occasional use of mild punishment may
sometimes be appropriate
• Verbal reprimands
• Removal of a reinforcer
• Time-outs
Observational Learning
• Observational learning occurs when an
organism’s response is influenced by the
observation of others as “models.”
• Psychologist Albert Bandura investigated
observational learning and identified four key
processes: attention, retention, reproduction,
and reinforcement.
• Influence of modeling is generally stronger when
the model is similar to learner and when the
model is positively reinforced for performing the
behavior.
• Fears may also be acquired by modeling.
Albert Bandura
*COMPARISON*
Classical
Conditioning
Occurs when
Nature of Response
Focuses on
Association Required
Learning takes place
when…
Operant
Conditioning
Behavior (response) is
followed by a
Two stimuli are paired
reinforcing stimulus
Involuntary
Voluntary
Simple
Complex
ANTECEDENTS:
CONSEQUENCES:
Events which take place Events which take place
BEFORE the target
AFTER the target
response
response
S
à R
An association is made
between two unrelated
stimuli
R à S
A desired response is
affected by its
consequences
YOUR TURN – SORTING TIME!
Classical Conditioning Operant Conditioning
Response is followed by a
Do homework, get a good
reinforcing stimulus
class
grade
Involuntary Candy in class, love
Yelled at by history teacher at of
Voluntarythe blue, never want toReinforced
take
Response
Participate
in class à get candy
Association
Stimulus, thenhistory
Response
again