Transcript Learning
Learning
Learning
“relatively permanent change in an
organism’s behavior due to experience”
HOWEVER: what most psych texts call
“Learning” the rest of us call
“motivation”
“Learning” = learning what is
rewarding and what isn’t.
Association
We learn by association
Our minds naturally connect events
that occur in sequence
Aristotle 2000 years ago
John Locke and David Hume 200 yrs
ago
Associative Learning
learning that two events occur together
two stimuli
a response and its consequences
Association
Event 1
Event 2
Learning to
associate
two events
Sea snail associates splash with a tail shock
Seal learns to expect a snack for its showy antics
Classical or Pavlovian
Conditioning
Classical Conditioning
organism comes to associate two stimuli
begins with a reflex (note that humans
don’t have many of these)
a neutral stimulus is paired (associated) with
a stimulus that evokes the reflex
neutral stimulus eventually comes to evoke
the reflex
Classical or Pavlovian
Conditioning
Ivan Pavlov
1849-1936
Russian physician/ neurophysiologist
Nobel Prize in 1904
studied digestive secretions
Maybe you’ve heard of “Pavlov’s dogs”…
Pavlov’s Classic
Experiment
Before Conditioning
UCS (food
in mouth)
UCR
(salivation)
During Conditioning
Neutral
stimulus
(tone)
No
salivation
After Conditioning
UCS (food
in mouth)
Neutral
stimulus
(tone)
UCR
(salivation)
CS
(tone)
CR (salivation)
Classical or Pavlovian
Conditioning
Unconditioned Stimulus (UCS)
effective stimulus that unconditionallyautomatically and naturally- triggers a
response
Unconditioned Response (UCR)
unlearned, naturally occurring automatic
response to the unconditioned stimulus
salivation when food is in the mouth
Classical or Pavlovian
Conditioning
Conditioned Stimulus (CS)
previously neutral stimulus that, after
association with an unconditioned stimulus,
comes to trigger a conditioned response
Conditioned Response (CR)
learned response to a previously neutral
conditioned stimulus
Dr Fred’s handy guide to
classical conditioning
1 – remember that humans salivate to the
smell of food just like dogs (reflex!)
2 – freshly baked donuts smell great
3 – so….
Dr Fred’s handy guide to
classical conditioning
Modern
Classical
Conditioning
Classical or Pavlovian
Conditioning
Spontaneous Recovery
reappearance, after a rest period, of an
extinguished CR
Generalization
tendency for a stimuli similar to CS to evoke
similar responses
Interstimulus interval
Time between the CS and the UCS
Optimal usually .5-5 seconds but Garcia effect!
Classical or Pavlovian
Conditioning
Blocking
Prior learning hinders later learning
e.g., dog learned to salivate to bell, now use a light – ineffective!
Latent inhibition
early exposure to a neutral stimulus without a
UCS slows later learning of a CS-UCS association
for that stimulus
Prepared learning
Some responses easier to learn - evolutionary
predisposition to that response
Operant Conditioning
(aka “Behaviorism”)
Operant Conditioning
type of learning in which behavior is
strengthened if followed by reinforcement or
diminished if followed by punishment
Law of Effect
Thorndike’s principle that behaviors followed
by favorable consequences become more
likely and behaviors followed by unfavorable
consequences become less likely
Behaviorism
John B. Watson
viewed psychology as objective
science
generally agreed-upon consensus
today
recommended study of behavior
without reference to unobservable
mental processes
not universally accepted by all
schools of thought today
Behaviorism
B.F. Skinner (1904-1990)
elaborated Thorndike’s Law of
Effect
developed behavioral technology:
The “Skinner Box”…
Operant Chamber
Skinner Box
soundproof
chamber with a
bar or key that an
animal presses or
pecks to release a
food or water
reward
contains a device
to record
responses
Operant Conditioning
= another form of associative
learning
We learn to
associate a
behavior and its
consequence
Hot stove =
pain
Some terms in both classical and
operant conditioning
Acquisition
the initial stage of learning, during which a
response is established and gradually
strengthened
in classical conditioning, the phase in which a
stimulus comes to evoke a conditioned
response
in operant conditioning, the strengthening of
a reinforced response
Some terms in both classical and
operant conditioning
Discrimination
in classical conditioning, the ability to
distinguish between a CS and other stimuli
that do not signal and UCS
in operant conditioning, responding
differently to stimuli that signal a behavior
will be reinforced or will not be reinforced
Some terms in both classical and
operant conditioning
Extinction
diminishing of a CR
in classical conditioning, when a
UCS does not follow a CS
in operant conditioning, when a
response is no longer reinforced
Operant Conditioning
Positive reinforcement
Negative reinforcement
BOTH are rewards
Both escape learning and avoidance
learning can occur with negative rein.
Positive punishment
Negative punishment
BOTH are punishments
Operant Conditioning
Shaping
conditioning procedure in which
reinforcers guide behavior toward closer
approximations of a desired goal
Successive Approximations
reward behaviors that increasingly
resemble desired behavior
Chaining
Stringing together sets of previously
shaped behaviors
Principles of
Reinforcement
Primary Reinforcer
innately reinforcing stimulus
satisfies a biological need
Secondary Reinforcer
conditioned reinforcer
learned through association with
primary reinforcer
Mechanisms of
Reinforcement
Drive reduction (homeostasis)
Association (secondary reinforcers)
Behavioral Approach System (BAS)
Distinct neural pathway for reward (left PFC)
Dopamine
Behavioral Inhibition System (BIS)
Distinct neural pathway for anxiety (right PFC)
Norepinephrine
Fight or Flight system (FFS) – sympathetic NS
Schedules of
Reinforcement
Continuous Reinforcement
reinforcing the desired response each time it
occurs
learning occurs rapidly
extinction occurs rapidly
Partial Reinforcement
reinforcing a response only part of the time
results in slower acquisition
greater resistance to extinction
Schedules of
Reinforcement
Fixed Ratio (FR)
reinforces a response only after a
specified number of responses
faster you respond the more rewards you
get
different ratios
very high rate of responding
like piecework pay
Schedules of
Reinforcement
Variable Ratio (VR)
reinforces a response after an
unpredictable number of responses
very hard to extinguish because of
unpredictability
And just in case you think this stuff
only applies to rats…
Skinner boxes for humans
Another form of variable
ratio reinforcement
Schedules of
Reinforcement
Fixed Interval (FI)
reinforces a response only after a
specified time has elapsed
response occurs more frequently as
the anticipated time for reward
draws near
Schedules of
Reinforcement
Variable Interval (VI)
reinforces a response at
unpredictable time intervals
produces slow steady responding
like pop quiz
Schedules of
Reinforcement
Number of
responses
1000
Fixed Ratio
Variable Ratio
Fixed Interval
750
Rapid responding
near time for
reinforcement
500
Variable Interval
250
Steady responding
0
10
20
30
40
50
Time (minutes)
60
70
80
Punishment
Punishment
aversive event that decreases
the behavior that it follows
powerful controller of unwanted
behavior
Problems with
Punishment
Punished behavior is not forgotten, it's
suppressed- behavior returns when
punishment is no longer imminent
Causes increased aggression- shows that
aggression is a way to cope with problemsExplains why aggressive delinquents and
abusive parents come from abusive homes
Regression to the mean - fools the punisher
More Problems with
Punishment
Creates fear that can generalize to desirable
behaviors, e.g. fear of school, learned
helplessness, depression
Does not necessarily guide toward desired
behavior- reinforcement tells you what to do-punishment tells you what not to doCombination of punishment and reward can be
more effective than punishment alone
Using punishment
wisely
The “hot stove” rule:
Punishment should be:
Immediate
Consistent
Impersonal
Cognitive Learning
(aka
Cognitive-social learning)
Cognition
thinking; information processing
input - processing/storage - output
Cognition = information processing and
storage (memory)
includes judgment, motivation, emotions,
etc.
Cognitive Learning
Cognitive Map
mental representation of the layout of one’s
environment
example- after exploring a maze, rats act as
if they have learned a cognitive map of it
Latent Learning
learning that occurs, but is not apparent until
there is an incentive to demonstrate it
Social Learning
Observational Learning
learning by observing and imitating others
{opportunity to practice!}
Modeling
process of observing and imitating behavior
Vicarious reinforcement (conditioning)
observing another’s consequences
Tutelage and mentoring
Cognitive Learning (aka
Cognitive-social learning)
More on this in chapter 7…