Upload
kimberly-flowers
View
216
Download
0
Tags:
Embed Size (px)
Citation preview
Mar
y Jo
nes
In This Chapter
Learning Through Classical Conditioning
Learning Through Operant Conditioning
Biological and Cognitive Aspects of Learning
Learning Through Classical Conditioning
The Elements and Procedures of Classical Conditioning
General Learning Processes in Classical Conditioning
Different Foci
Behavioral psychologists
• Focus on the learning of associations through classical conditioning and operant conditioning
Cognitive psychologists
• Are interested in the more complex type of learning involved in human memory
Learning Through Classical Conditioning
• Classical conditioning- Process of learning in which one stimulus signals
the arrival of another stimulus- Sometimes called “Pavlovian” conditioning- Ivan Pavlov was the first researcher to
systematically study this type of learning
Pavlov's Dog Study
Studying initial step in the digestive process• Dogs were strapped into
harnesses and had tubes inserted into their cheeks
• Amount of salivation was measured
• With time, the dogs started to salivate before the meat powder was even put in their mouths
This is a photograph of Pavlov's experimental laboratory.
The Elements and Proceduresof Classical Conditioning
• Neutral stimulus- Stimulus that does not naturally elicit the to-be-
conditioned response (e.g., auditory tones)
• Unconditioned stimulus (UCS)- Stimulus in a reflex that automatically elicits an
unconditioned response
• Unconditioned response (UCR) - Response in a reflex that is automatically elicited by
the unconditioned stimulus
The Elements and Procedures of Classical Conditioning
• Conditioned stimulus (CS)- Stimulus that comes to elicit a new response (the
conditioned response) in classical conditioning
• Conditioned response (CR) - Response that is elicited by the conditioned
stimulus in classical conditioning
Elements and Procedures of Classical Conditioning
Unconditioned Stimulus
(UCS)
Unconditioned Response
(UCR)
Conditioned Stimulus
(CS)
Conditioned Response
(CR)
Associated Similar
CS and CR
• To achieve conditioning, a tone (neutral stimulus) is presented just before the meat powder (USC) for several trials.
• Once the dog starts to salivate to the sound of the tone (conditioning) before the food is put in its mouth, the tone is now called the conditioned stimulus (CS).
• The learned response to the conditioned stimulus is called the conditioned response (CR).
Delayed and Trace Conditioning
• Delayed conditioning- Offset of the CS is delayed until after the UCS is presented so that the
two stimuli occur at the same time- Tone would be turned on and continue to sound until the meat powder
was placed in the dog's mouth- Delayed conditioning is the most effective procedure for classical
conditioning
• Trace conditioning- Period of time between the offset of the CS and the onset of the UCS
when neither stimulus is present- It is called “trace” conditioning because there must be a memory trace
of the CS for the association between stimuli to be learned- Trace conditioning can be effective provided the interval between stimuli
is brief
A Classical Conditioning Experiment
The Elements of Classical Conditioning
The “Little Albert” Study
John Watson and Rosalie Rayner conducted a
study on an 11-month-old infant named Albert
While Albert was looking at a little white rat, Watson quietly sneaked behind him with a long iron bar and a hammer
and clanged the two together
Albert's reflexive response, the UCR, was a fear-
avoidance response to the loud noise, which was the
UCS
After pairing the white rat with the unexpected loud
noise only 7 times, the white rat became a ______?
Fear and Positive Emotions
• Deconditioned a preexisting fear of rabbits in a 3-year-old boy
Mary Cover Jones • Unable to condition
infants to fear inanimate objects such as wooden blocks and cloth curtains
• Concluded possible biological predispositions to learn certain fears more easily than others
Elsie Bregman: Fear study
Fear and Positive Emotions
• Positive emotions- Classical conditioning can be used in advertising
to condition positive attitudes and feelings toward certain products
Do you have a favorite beverage? Have you ever seen or heard it advertised in the media?
General Learning Processes in Classical Conditioning
• Acquisition- Process of acquiring a new response, that is, a
CR to a CS- Strength of the CR increases during acquisition
General Learning Processes in Classical Conditioning
• Other Processes- Extinction- Spontaneous recovery- Stimulus generalization- Stimulus discrimination
Let's look at each of these more closely.
Extinction
Extinction
Disappearance of the CR when the UCS no longer follows the CSCS must reliably signal that the UCS is comingStrength of the CR decreases during extinction
Spontaneous Recovery
Spontaneous recovery
Acquisition, Extinction, and Spontaneous Recovery
Stimulus Generalization and Stimulus Discrimination
• Stimulus generalization- Elicitation of the CR to
a stimulus similar to the CS
- The more similar the stimulus is to the CS, the stronger the response will be
• Stimulus discrimination- Learning to give the
CR only to the CS or only to a small set of very similar stimuli, including the CS
- Overgeneralizing a response may not be adaptive; people need to learn to discriminate among stimuli
Discrimination Training
• Discrimination training- Person presented many different stimuli
numerous times- UCS only follows one CS- Procedure will extinguish the responses to other
stimuli
Stimulus Generalization and Discrimination
Learning Through Operant ConditioningLearning Through Reinforcement and Punishment
General Learning Processes in Operant Conditioning
Partial-Reinforcement Schedules in Operant Conditioning
Motivation, Behavior, and Reinforcement
Operant Conditioning
Learning to associate behaviors with their consequences• Behaviors that are reinforced (lead to
satisfying consequences) will be strengthened
• Behaviors that are punished (lead to unsatisfying consequences) will be weakened
The Law of Effect
•Any behavior that results in satisfying consequences tends to be repeated
•Any behavior that results in unsatisfying consequences tends not be repeated
Thorndike's Law of Effect
Thorndyke's Puzzle Boxes
• Edward Thorndike used puzzle boxes in his classic learning studies with cats. The boxes varied in how difficult they were for the cats to escape from.
• The results of these puzzle box experiments led Thorndike to develop the law of effect. Sci
ence
Sou
rce
Learning Through Reinforcement and Punishment
Reinforcer
•Stimulus that increases the probability of a prior response
Reinforcement
•Process by which the probability of a response is increased by the presentation of a reinforcer following the response
Learning Through Reinforcement and Punishment
Punisher•Stimulus that decreases the probability of a prior response
Punishment
•Process by which the probability of a response is decreased by the presentation of a punisher following the response
Positive and Negative Reinforcement and Punishment
Positive means that a stimulus is presented• In both positive
reinforcement and positive punishment, a stimulus presented
Negative means that a stimulus is removed• In both negative
reinforcement and negative punishment, a stimulus is removed
Appetitive and Aversive
Appetitive stimulus• Stimulus that an organism
finds pleasing • Example: Food, money
Aversive stimulus• Stimulus that an organism
finds unpleasing • Example: Sickness, social
isolation
Positive and Negative Reinforcement and Punishment
• Positive means that something is presented, and negative means that something is taken away
• Reinforcement means that the behavior is strengthened, and punishment means that the behavior weakened
• In positive reinforcement, and appetitive stimulus is presented, and in positive punishment, an aversive (unpleasant) stimulus is presented
• In negative reinforcement, an aversive stimulus is removed, and in negative punishment, an appetitive stimulus is removed
How do we know?
• In any example of positive or negative reinforcement or punishment- It is critical to realize that we only know if a
stimulus has served as a reinforcer or a punisher and led to reinforcement or punishment
- If the behavior happens again or stops happening
One More…
• Premack Principle- The opportunity to perform a highly frequent
behavior can reinforce a less frequent behavior.
- Reinforcers are viewed as sequence of behaviors rather than stimuli: Behavior that is being reinforced followed by the behavior that is the reinforcer.
Primary and Secondary Reinforcers
• Behavior modification- Application of classical and operant conditioning
principles to eliminate undesirable behavior and teach more desirable behavior
• Token economies
Primary and Secondary Reinforcers
• Primary reinforcer- Innately reinforcing since birth- Example: Food, social contact
• Secondary reinforcer- Not innately reinforcing, but gains reinforcing
properties through learning- Example: Money, good grades
Primary and Secondary Reinforcers
• Reinforcement without awareness (Hefferline and colleagues)- Demonstrated operant conditioning can occur
without person's awareness in task involving miniscule muscular response to harsh noise and soothing music
- Later demonstrated similar finding in decision-making task
General Learning Processes in Operant Conditioning
• Shaping- Occurs when an animal is trained to make a particular
response by reinforcing successively closer approximations to the desired response
- With humans, this might mean reinforcing a child the closer he comes to making his bed correctly each morning
• Cumulative record - Includes record of the total number of responses over time in
an operant conditioning experiment- Is a visual depiction of the rate of responding- What happens as the slope of the line in a cumulative record
gets steeper?
How to Understand a Cumulative Record
• By measuring how responses cumulate over time, a cumulative record shows the rate of responding
• When no responses occur, the record is flat (has no slope)
• As the number of responses increases per unit of time, the cumulative total rises more quickly
• The response rate is reflected in the slope of the record
• The faster the response rate, the steeper the slope of the record
Acquisition, Extinction, and Spontaneous Recovery
Acquisition • Strengthening
of the reinforced operant response
Extinction• Disappearance
of the operant response when it is no longer reinforced
Spontaneous recovery• Temporary
recovery of the operant response following a break during extinction training
Cumulative Record Illustrations of Acquisition, Extinction, and Spontaneous Recovery
Discrimination and Generalization
• Discriminative stimulus- Stimulus that has to be present for the operant
response to be reinforced- “Sets the occasion” for the response to be
reinforced
• Stimulus generalization- Giving the operant response in the presence of
stimuli similar to the discriminative stimulus
Partial-Reinforcement Schedules in Operant Conditioning
• Continuous schedule of reinforcement- Reinforcing every response
• Partial schedules of reinforcement- Reinforcing behavior only part of the time
Partial-Reinforcement Schedules in Operant Conditioning
• Continuous schedule of reinforcement- Reinforcing the desired operant response each time it is
made
• Partial schedule of reinforcement- Reinforcing the desired operant response only part of the
time
• Partial-reinforcement effect- The finding that operant responses that are reinforced on
partial schedules are more resistant to extinction than those reinforced on a continuous schedule
Partial-Reinforcement Schedules in Operant Conditioning
• Fixed-ratio schedule- Partial schedule of reinforcement in which a
reinforcer is delivered each time a fixed number of responses is made. The fixed number can be any number greater than one.
• Variable-ratio schedule- Partial schedule of reinforcement in which the
number of responses it takes to obtain a reinforcer varies on each trial but averages to a set number across trials.
Fixed Ratio and Variable Ratio Schedules of Partial Reinforcement
Interval Schedules
Fixed interval schedule
Variable interval
schedule
Fixed Interval and Variable Interval Schedules of Partial Reinforcement
Which schedule is best?
Ratio schedules lead to higher rates of responding than interval schedules (steeper slopes on the cumulative record)
With respect to extinction, it will take longer to extinguish a response with a partial-reinforcement schedule than a continuous reinforcement
Variable schedules lead to fewer breaks (no responding occurring) after reinforcement than fixed schedules
Motivation, Behavior, and Reinforcement
• Motivation- Set of internal and external factors that energize
behavior and direct it toward goals
Theories of Motivation
•Bodily need (such as hunger) creates a state of bodily tension called drive
•Motivated behavior (seeking food) works to reduce this drive
•This is done by obtaining reinforcement (food) to eliminate this need and return the body to a balanced internal state
Drive-reduction theory
Theories of Motivation
•Proposes that we are “pulled” into action by incentives
•Incentives are external environmental stimuli that do not involve drive reduction
Incentive theory
Theories of Motivation
•Behavior is motivated to maintain an optimal level of arousal, which varies among people
•When below the optimal level, people are motivated to raise arousal to that level
•When over-aroused, people are motivated to lower arousal level to the optimal level
Arousal theory
The Yerkes-Dodson Law
• Increased arousal will aid performance up to a point, after which further arousal impairs performance
Extrinsic vs. Intrinsic Motivation
• Extrinsic motivation - Desire to perform behavior to obtain an external
reinforcement or to avoid an external aversive stimulus
• Intrinsic motivation- Desire to perform a behavior effectively for its
own sake- Reinforcement is provided by the activity itself
The Overjustification Effect
• Lepper, Greene, and Nisbett (1973)- Some children who enjoyed playing with felt-tipped
pens were given prizes, an extrinsic incentive, for playing with the pens
- Other such children were not given prizes for playing with the pens
• Using the overjustification effect, how do you predict each group of children will play with the pens when the prizes are removed a week later?
The Overjustification Effect
• Why does it occur?- The overjustification effect indicates that a
person's cognitive processing influences behavior and that such processing may lessen the effectiveness of extrinsic reinforcers
- However, extrinsic reinforcement is not likely to impact intrinsic motivation if the extrinsic reinforcement is dependent upon doing something well versus just doing it
Biological and Cognitive Aspects of Learning
Biological Preparedness in Learning
Latent Learning and Observational Learning
Biological Preparedness in Learning
True or false?• Our preparedness to learn to fear objects
dangerous to us and to avoid foods and drinks that make us sick has adaptive significance.
Taste Aversion
Garcia and Koelling (1966):
Rat radiation study
After several radiation
treatments, rats entered
experimental cages but did not drink
waterDifferences in water bottles in
experimental and non-experimental
cages created different tasting
waters
Rats learned aversion to to
experimental cage water bottles
Researchers examined two cues
that were both paired with
sickness through radiation: Sweet-tasting water and
normal tasting water with clicking noises and flashing
lightsLet's see what happened next.
Taste Aversion
Rats that drank the sweet-tasting water easily learned the
aversion to the water
Rats that drank normal-tasting water while they
experienced clicking noises and flashing lights
did not do so
Rats just could not learn to pair these environmental
auditory and visual cues that occurred during their drinking
with their later sickness
The pairing did not make any
“biological” sense to the rats
Instinctual Drift
• Instinctual drift- Tendency of an animal to drift back from learned
operant response to an object to an innate, instinctual response
- Involves biologically instinctual responses that sometimes limit or hinder ability to condition other less natural responses
- Suggests organisms will learn certain associations more easily than others
Instinctual Drift
As shown in these photos, pigs are biologically predisposed to root out their food and raccoons are biologically predisposed to wash their food.
Latent Learning and Observational Learning
• Latent learning- Learning that occurs
but is not demonstrated until there is incentive to do so
• Observational learning (modeling)- Learning by observing
others and imitating their behavior
Edward Tolman pioneered latent-learning research with rats.
Arch
ives
of t
he H
istor
y of
Am
eric
an P
sych
olog
y
Latent Learning
Observational Learning
Albert Bandura's pioneering research on modeling: Bobo doll experiment• Children were exposed to an adult who beats, kicks, and
yells at a Bobo doll or to a room with a gentler adult model
• They were later taken to another room with accessible toys, including a Bobo doll
• When exposed to a gentle model, children acted more gently toward the doll than children exposed to the aggressive model
• Children's behavior was guided by the behavior of the model to which they were exposed
Observational Learning
• Bandura's Bobo doll research- In another experiment, an adult was rewarded for
aggressive behavior, punished for aggressive behavior, or received no consequences
- Children who saw the adult get reinforced for aggressive behavior acted more aggressively toward the Bobo doll than those who had seen the model act with no consequences
- Children who had watched the adult get punished were less likely to act aggressively toward the doll than children who had not been exposed to any consequences for acting aggressively toward the doll
Bobo Doll Experiments
These photographs of the children in the Bobo doll experiments imitating the violent behavior of the adult model show the powerful influence of observational learning.
Courtesy Albert Bandura, Stanford University
Media Violence
• Research on violent television and films, video games, and music- Reveals unequivocal evidence that media violence
increases the likelihood of aggressive and violent behavior in both immediate and long-term contexts
• Mirror neurons- Recent research by neuroscientists has led to the
discovery of neuron systems that provide a neural basis for observational learning