Transcript Chapter 6 Learning - Home | W. W. Norton & Company

6.1 What are
the three ways
we learn?
6.2 How do we learn by
classical conditioning?
Ch. 6
Learning
6.4 How do we learn by
watching others?
6.3 How do we learn by
operant conditioning?
6.1 What Are the
Three Ways We Learn?
• Learning: a relatively enduring change in
behavior due to experience
– Central to almost all areas of human existence
We Learn From Experience
• Behaviorism: a formal learning theory from
the early twentieth century
– John Watson: focused on environment and
associated effects as key determinants of learning
– B. F. Skinner: designed animal experiments to
discover basic rules of learning
We Learn From Experience
• Critical for survival
• Adapt behaviors for a particular environment
– Which sounds indicate potential danger?
– What foods are dangerous?
– When is it safe to sleep?
We Learn in Three Ways
1. Non-associative learning
2. Associative learning
3. By watching others
• Let’s look at these on the following slides
We Learn in Three Ways
1. Non-associative learning: information about
one external stimulus (e.g., a sight, smell,
sound)
We Learn in Three Ways
• 1a. Habituation: exposure to a stimulus for a
long time, or repeatedly, leads to a decrease in
behavioral response
– Especially if the stimulus is neither harmful nor
rewarding
• See Figure 6.2a on the next slide . . .
We Learn in Three Ways
We Learn in Three Ways
• 1b. Sensitization: exposure to a stimulus over
a long time, or repeatedly, leads to an increase
in behavioral response
– Heightened preparation in a situation with
potential harm or reward
• See Figure 6.2b on the next slide . . .
We Learn in Three Ways
We Learn in Three Ways
• 2. Associative learning: understanding how
two or more pieces of information are related
We Learn in Three Ways
• 2a. Classical conditioning: learn that two
stimuli go together
– Example: music from scary movies elicits
anxiousness when heard
• 2b. Operant conditioning: learn that a
behavior leads to a particular outcome
– Example: studying leads to better grades
We Learn in Three Ways
• 3. Learning by watching others
– Observational learning
– Modeling
– Vicarious conditioning
The Brain Changes During Learning
• Long-term potentiation (LTP): the
strengthening of synaptic connections
between neurons
– Recall that “cells that fire together, wire together”
– Exposure to environmental events causes changes
in the brain to allow learning
6.1 What are the three
ways we learn?
6.2 How do we
learn by classical
conditioning?
Ch. 6
Learning
6.4 How do we learn by
watching others?
6.3 How do we learn by
operant conditioning?
6.2 How Do We Learn By
Classical Conditioning?
• Familiar example: association between scary
music in movies and bad things happening to
characters
Through Classical Conditioning,
We Learn That Stimuli Are Related
• Pavlov: Nobel Prize in 1904 for research on
the digestive system
• Observed dogs began to salivate as soon as
they saw bowls of food
– Salivating at sight of a bowl is not automatic
– Behavior acquired through learning by association
• See Figure 6.3b on the next slide . . .
Through Classical Conditioning,
We Learn Stimuli Are Related
Pavlov’s Experiments Reveal the
Four Steps in Classical Conditioning
• Classical conditioning: learning begins with a
stimulus that naturally elicits a response
– Much like a reflex
Pavlov’s Experiments Reveal the
Four Steps in Classical Conditioning
• Four key steps:
1. Present unconditioned stimulus: evokes
unlearned response
2. Present neutral stimulus: no response
3. Pair stimuli from Steps 1 and 2: learned response
(conditioning trials)
4. Neutral stimulus alone will trigger learned
response (critical trials)
• Let’s look at this on the next slide
Pavlov’s Experiments Reveal the
Four Steps in Classical Conditioning
• Step 1: presenting food causes salivary reflex
– Unconditioned stimulus (US): nothing is learned
about the stimulus (e.g., food)
– Unconditioned response (UR): an unlearned
behavior, like a simple reflex (e.g., salivation)
Pavlov’s Experiments Reveal the
Four Steps in Classical Conditioning
• Step 2: clicking metronome is neutral stimulus
– Neutral stimulus: anything seen or heard; must
not associate with the unconditioned response
Pavlov’s Experiments Reveal the
Four Steps in Classical Conditioning
• Step 3 (conditioning trials): start of learning
– Dog begins to associate US (food) and neutral
stimulus (metronome)
Pavlov’s Experiments Reveal the
Four Steps in Classical Conditioning
• Step 4 (critical trials): association learned
– Metronome alone, without food, makes dog
salivate
• See Figure 6.3 on the next slide . . .
Pavlov’s Experiments Reveal the
Four Steps in Classical Conditioning
Pavlov’s Experiments Reveal the
Four Steps in Classical Conditioning
• Conditioned stimulus (CS): after conditioning,
previously neutral stimulus (NS) reliably
produces unconditioned response (UR)
• Conditioned response (CR): behavior only
after conditioning; usually weaker than
unconditioned response
Learning Varies in
Classical Conditioning
• Animals adapt via conditioning
• Learning to predict outcomes leads to new
adaptive behaviors
Acquisition, Extinction, and
Spontaneous Recovery
• Acquisition: gradual formation of learned
association between CS and US to produce CR
– Strongest conditioning occurs when CS is
presented slightly before US
• See Figure 6.5a on the next slide . . .
Acquisition, Extinction, and
Spontaneous Recovery
Acquisition, Extinction, and
Spontaneous Recovery
• Extinction: CS no longer predicts arrival of US
• Sometimes associations are no longer
adaptive
• See Figure 6.5b on the next slide . . .
Acquisition, Extinction, and
Spontaneous Recovery
Acquisition, Extinction, and
Spontaneous Recovery
• Spontaneous recovery: original association
between CS and US is relearned
• Can occur after only one pairing following
extinction
– Response will get weaken if CS-US pairings do not
continue
• See Figure 6.5d on the next slide . . .
Acquisition, Extinction, and
Spontaneous Recovery
Generalization, Discrimination, and
Second-Order Conditioning
• Stimulus generalization: stimuli similar, but
not identical to, CS that produces CR
– Animals respond to variations in CS
• See Figure 6.6 on the next slide . . .
Generalization, Discrimination, and
Second-Order Conditioning
Generalization, Discrimination, and
Second-Order Conditioning
• Stimulus discrimination: differentiate
between similar stimuli; one is consistently
associated with US and the other is not
• See Figure 6.7 on the next slide . . .
Generalization, Discrimination, and
Second-Order Conditioning
Generalization, Discrimination, and
Second-Order Conditioning
• Second-order conditioning: second CS
becomes associated with first CS; elicits CR
when presented alone
• Neither US nor original CS present
– Example: pairing black square (second CS) with
metronome (first CS) so black square produces
salivation (CR) on its own
We Learn Fear Responses Through
Classical Conditioning
• Phobia: acquired fear that is very strong in
comparison to threat
The Case of Little Albert
• Classical conditioning demonstrated in
phobias:
– Showed “Little Albert” various neutral objects
(e.g., white rat, rabbit, dog, monkey, white
wool)
– Paired rat (CS) and loud clanging (US) until rat
alone produced fear (CR)
• Fear generalized to all similar stimuli
• See Figure 6.8 on the next slide . . .
The Case of Little Albert
Counterconditioning
• Classical conditioning techniques valuable in
treating phobias
Counterconditioning
• Counterconditioning: exposing subject to phobia
during an enjoyable task
• Systematic desensitization: exposure to feared
stimulus while relaxing
– CS -> CR1 (fear) connection replaced with CS -> CR2
(relaxation) connection
Adaptation and Cognition Influence
Classical Conditioning
• Pavlov’s belief: any two events presented
together would produce learned association
• By 1960s, data suggested that some
conditioned stimuli more likely to produce
learning
Evolutionary Influences
• Certain pairings more likely to be associated
– Conditioned taste aversions: easy to produce with
smell or taste cues
– Auditory and visual stimuli: value for signaling
danger
Cognitive Influences
• Through classical conditioning, animals predict
events
– Easier when CS before US rather than after US
– Easier when CS is more unexpected or surprising
6.1 What are the three
ways we learn?
6.2 How do we learn by
classical conditioning?
Ch. 6:
Learning
6.4 How do we learn by
watching others?
6.3 How do we
learn by operant
conditioning?
6.3 How Do We Learn by
Operant Conditioning?
• Human behaviors are purposeful
• Operant conditioning: relationship between
behavior and consequences
We Learn Effects of Behavior
Through Operant Conditioning
• Operant conditioning: animals operate on
environments to produce effects
• Consequences determine likelihood of
behavior in future
Thorndike’s Experiments Reveal the
Effects of Action
• Thorndike’s puzzle box: challenged fooddeprived animals to find escape
– Trap door would open if animal performed specific
action
– Animal quickly learned to repeat behavior to free
itself and reach the food
• See Figure 6.10 on the next slide . . .
Thorndike’s Experiments Reveal the
Effects of Action
Thorndike’s Experiments Reveal the
Effects of Action
• Thorndike’s general theory of learning
– Law of effect: any behavior leading to a “satisfying
state of affairs” likely to be repeated
– Any behavior leading to an “annoying state of
affairs” less likely to reoccur
Learning Varies in
Operant Conditioning
• B. F. Skinner’s learning theory based on the
law of effect:
– Reinforcer: stimulus occurs after response and
increases likelihood of response reoccurring
• Believed that behavior occurs because
reinforced
Shaping
• Shaping: operant-conditioning technique;
reinforce behaviors increasingly similar to
desired behavior
• See Figure 6.12 on the next slide . . .
Shaping
Reinforcers Can Be Conditioned
• Primary reinforcers: satisfy biological needs,
necessary for survival (e.g., food, water)
• Secondary reinforcers: serve as reinforcers, do
not satisfy biological needs; established
through classical conditioning
Reinforcer Potency
• Some reinforcers are more powerful
• Premack principle: more valued activity can
reinforce performance of less valued activity
– Example: “Eat your spinach and then you’ll get
dessert.”
Reinforcement and Punishment
Influence Operant Conditioning
• Reinforcement and punishment have opposite
effects on behavior
– Reinforcement: behavior more likely to be
repeated
– Punishment: behavior less likely to occur again
Positive and Negative Reinforcement
• Both positive and negative reinforcement
increase likelihood of a given behavior
Positive and Negative Reinforcement
• Positive reinforcement: addition of stimulus
that increases probability behavior will
reoccur
– Example: feeding a rat after it has pressed a lever
• Negative reinforcement: removal of stimulus
that increases likelihood of given behavior
– Example: taking a pill to get rid of a headache
Positive and Negative Reinforcement
• Both positive and negative punishment reduce
likelihood that behavior will be repeated
Positive and Negative Reinforcement
• Positive punishment: addition of stimulus
decreases probability of behavior being
repeated
– Example: electrical shock, speeding ticket
• Negative punishment: removal of stimulus
decreases probability of behavior being
repeated
– Example: loss of food, loss of privileges
Schedules of Reinforcement
1. Continuous reinforcement: behavior
reinforced each time it occurs
– Fast learning, uncommon in real world
2. Partial reinforcement: behavior is
occasionally reinforced
– More common in real world
Schedules of Reinforcement
• How reinforcement given x how consistently
given = four common schedules
1.
2.
3.
4.
Fixed schedule: predictable basis
Variable schedule: unpredictable basis
Interval schedule: based on passage of time
Ratio schedule: based on number of responses
• See Figure 6.15 on the next slide . . .
Schedules of Reinforcement
Schedules of Reinforcement
1. Fixed interval schedule (FI): reinforcement after
fixed amount of time
– Example: paycheck
2. Variable interval schedule (VI): reinforcement after
unpredictable amount of time
– Example: pop quiz
– More consistent response rates than fixed interval
Schedules of Reinforcement
3. Fixed ratio schedule: reinforcement after fixed
number of responses
– Example: paid by the completed task
– Often yields better response rates than fixed interval
4. Variable ratio schedule: reinforcement after variable
number of responses
– Example: slot machine
Schedules of Reinforcement
• Partial-reinforcement extinction effect:
behavior lasts longer under partial
reinforcement than under continuous
reinforcement
• To condition behavior to persist:
– Use continuous reinforcement initially
– Slowly change to partial reinforcement
Operant Conditioning Affects Our Lives
• Imagine a parent says no to a candy bar, so
child throws a tantrum
– Parent yells, “If you don’t stop screaming, you’re
going to get a smacked bottom!”
• Will this approach get the desired behavior?
Parental Punishment Is Ineffective
• To be effective, punishment must be:
– Reasonable
– Unpleasant
– Applied immediately
– Clearly connected to the unwanted behavior
Parental Punishment Is Ineffective
• Punishment can cause confusion:
– Wrongly applied after desirable behavior
– Leads to negative emotions (e.g., fear, anxiety)
– Fails to offset reinforcing aspects of the undesired
behavior
• Reinforcement teaches desirable behavior
• See Figure 6.16 on the next slide . . .
Parental Punishment Is Ineffective
Behavior Modifications
• Behavior modification: operant conditioning
replaces unwanted behaviors with desirable
behaviors
• Most unwanted behaviors can be unlearned
Behavior Modifications
• Token economies: opportunity to earn tokens
(secondary reinforcers) for completing tasks
and lose tokens for behaving badly
– Tokens later traded for objects or privileges
• Gives participants sense of control
Biology and Cognition Influence
Operant Conditioning
• Behaviorists believed conditioning principles
explained all behavior
• In reality, reinforcement explains only a
certain amount of human behavior
Dopamine Activity
Affects Reinforcement
• Biological influence on how reinforcing
something is
– Drugs that block dopamine’s effects disrupt
operant conditioning
– Drugs that enhance dopamine activation increase
reinforcing value of stimuli
Biology Constrains Reinforcement
• Some animal behaviors hardwired
– Difficult to learn behaviors counter to evolutionary
adaptation
• Conditioning most effective when matched to
animal’s biological predispositions
Learning Without Reinforcement
• Tolman argued that reinforcement impacts
performance more than knowledge
acquisition
– Ran rats through complex mazes to obtain food
– Cognitive map: maze-specific mental
representation that Tolman believed each rat
developed
Learning Without Reinforcement
• Three groups of rats traveled maze
– Group 1: no reinforcement
– Group 2: reinforcement every trial
– Group 3: reinforcement only after first 10
trials
• See Figure 6.19 on the next slide . . .
Learning Without Reinforcement
Learning Without Reinforcement
• Latent learning: learning without
reinforcement
• Group 1: slow, many wrong turns
• Group 2: faster, fewer errors each trial
• Group 3:
– Before reinforcement, similar to Group 1
– After reinforcement, better than Group 2
Learning Without Reinforcement
• Insight learning: solution suddenly emerges
after delay; type of problem solving
• Reinforcement does not fully explain but
predicts behavior’s repetition
6.1 What are the three
ways we learn?
6.2 How do we learn by
classical conditioning?
Ch. 6:
Learning
6.4 How do we
learn by
watching others?
6.3 How do we learn by
operant conditioning?
6.4 How Do We Learn by
Watching Others?
• Behaviors we learn by watching others:
– Mechanical skills, social etiquette, situational
anxiety, attitudes about politics and religion
• Three ways we learn by watching:
1. Observational learning
2. Modeling
3. Vicarious conditioning
Three Ways We Learn
Through Watching
1. Observational learning: individual acquires or
changes behavior after viewing it at least once
– Examples: foods safe to eat, objects and situations
to fear
• Powerful adaptive tool
• See Figure 6.20 on next slide . . .
Three Ways We Learn
Through Watching
Bandura’s Research Reveals
Learning Through Observation
• Observation of aggression: Bandura’s Bobo
doll study
– Group 1: watched film of adult playing quietly
with Bobo, an inflatable doll
– Group 2: watched film of adult attacking Bobo
• Viewers of aggression were more than twice
as likely to play aggressively
Learning Through Modeling
2. Modeling: imitation of observed behavior
• More likely to imitate actions of attractive,
high-status models similar to ourselves
• See Figure 6.22 on the next slide . . .
Learning Through Modeling
Learning Through
Vicarious Conditioning
3. Vicarious conditioning: learning about
consequences by watching others
– Rewarded behavior more imitated
– Punished behavior less imitated
• See Figure 6.23 on the next slide . . .
Learning Through
Vicarious Conditioning
Watching Others Results in
Cultural Transmission
• Meme: shared piece of cultural knowledge
– Similar to genes, selectively passed across
generations, can spread much faster
– Animals also show this kind of knowledge sharing
• See Figure 6.24 on the next slide . . .
Watching Others Results in
Cultural Transmission
Biology Influences
Observational Learning
• Mirror neurons: fire in your brain and other
person’s brain every time you watch them
engaging in an action
– Does not always lead to imitation
• Scientists still debating mirror neurons’
function