Download Basic Principles of Learning

Basic Principles
of Learning
Basic Principles of Learning
Definition of Learning
• Relative permanent change in behavior
brought about through experience or
interactions with the environment
– Not all changes result from learning
– Change in behavior not always immediate
• Years of isolating and studying behavior
produced different principles of learning
Basic Principles of Learning
Classical Conditioning:
Learning by Association
• Ivan Pavlov in Russia
– Nobel Prize for saliva in digestion
– Reflexive response controlled by arbitrary
stimulus (salivation when attendant approached)
• Association - key element
– First recognized by Aristotle
– Pavlov: classical conditioning was form of
learning through association
Pavlov’s Experiment
Observation screen
Container of
meat powder
Revolving drum for
recording responses
Device to count
drops of saliva
Tube for
collection
of saliva
Neutral stimulus
(metronome)
C
UCR
(meat powder)
UCR (salivation)
Conditioning procedure: during the
classical conditioning procedure, the
neutral stimulus is presented in association
with the unconditioned stimulus (UCS) to
elicit the unconditioned response (UCR)
D
CS (metronome)
CR (salivation)
Test of conditioning: after classical
conditioning, the neutral stimulus
becomes a conditioned stimulus (CS)
that elicits the conditioned response
(CR) of salivation
Basic Principles of Learning
Pavlov’s Experiments
• Systematic, effective, precise studies
• Association of two stimuli
• The more frequently the metronome and
food are associated, the more often the
metronome will elicit salivation
• Timing of association is highly important
– Longer time intervals were less effective;
almost no learning occurred
Pavlov’s Studies: the more often the
metronome was associated in time with meat
powder, the more effective in eliciting saliva
8
7
Number of
drops of
saliva
elicited by
metronome
alone
6
5
4
3
2
1
1
2
3
4
5
6
7
8
9
10
11
Number of times metronome and meat powder were presented together
Pavlov’s Experiment
A
Neutral stimulus
(metronome)
CR (salivation)
Before classical conditioning: initially,
the metronome is a neutral stimulus that
does not elicit the response of salivation
B
UCR
(meat powder)
UCR (salivation)
But the unconditioned stimulus
(UCS) can elicit the unconditioned
response (UCR)
Basic Principles of Learning
Terminology of Classical Conditioning
• Unconditioned stimulus (UCS)
– Elicits response without learning
• Unconditioned response (UCR)
– Unlearned, inborn response
• Conditioned stimulus (CS)
– Acquires ability to elicit after paired
association with unconditioned stimulus
• Conditioned response (CR)
– Elicited by conditioned stimulus
Application of Terminology
to Pavlov’s Experiment
CS
(meat powder)
CR
UCR (Salivation)
UCS
(metronome)
Basic Principles of Learning
Definition of Classical Conditioning
• Form of learning in which
– CS followed by UCS elicits UCR
– Pairing of CS and UCS allows CS to elicit CR
almost identical or similar to UCR
• Considered learning because
– New behavior acquired
– Old behavior elicited by new stimulus
– Does not depend on behavior of individual
Basic Principles of Learning
Importance of Classical Conditioning
• Watson and Rayner
– Made classical conditioning famous with
Little Albert experiments
• Learned to fear rats - unethical today
• Watson and Jones
– Counterconditioning: reversing the CR
• Useful in
– Explaining aspects of human health
– Explaining sexual fetishes and arousals
Watson and Raynor Study
CS
(rat)
CR
UCR
UCS
(loud noise)
(fear)
Basic Principles of Learning
Operant Conditioning: Learning from
the Consequences of Your Behavior
• Form of learning
– Consequences of behavior lead to change based
on probability of consequences occurring
• Thorndike and the puzzle box
– Researching animal intelligence
– Law of effect: consequences determine
response occurring in future
Basic Principles of Learning
Operant Conditioning
• Three types of desirable and undesirable
consequences that influence behavior
– Positive reinforcement
– Negative reinforcement
– Punishment
Basic Principles of Learning
Reinforcement
• Positive reinforcers – learned and inborn
• Primary reinforcement
– Innately reinforcing
– Examples: food, water, warmth, physical activity
• Secondary reinforcement
– Learned through classical conditioning
– Examples: rewards, money, praise
Primary reinforcer
Secondary reinforcer
Basic Principles of Learning
Schedules of Positive Reinforcement
• Continuous – reinforcer for every response
• Schedules
– Fixed ratio – reinforcer given after each
specified or fixed number of responses
– Variable ratio – reinforcement after varying
number of responses
Patterns of Behavior Produced
by Reinforcement
Fixed Ratio
Time
Variable Ratio
Time
Basic Principles of Learning
Schedules of Positive Reinforcement
• Schedules
– Fixed interval schedule – reinforcement
based on time (ie: every 2 hours)
– Variable interval schedule – reinforcement
after variable amount of time (ie: reinforced
after 1 hour, then after 4 minutes, then after
35 minutes like slot machine gambling)
Patterns of Behavior Produced
by Reinforcement
Fixed Interval
Time
Variable Interval
Time
Basic Principles of Learning
Shaping
• Reinforcing steps toward targeted behavior
or method of successive approximations
• Skinner – Skinner box
– Rat pushes lever to get food after
• Rewarded for steps of nearing, touching,
and pushing on lever
• Used for children and those with
developmental handicaps
Operant Conditioning
Signal
lights
Speaker
Lever
Pellet
dispenser
To shock
generator
Dispenser
tube
Food cup
Electric grid
Basic Principles of Learning
Negative Reinforcement
• Something unpleasant, aversive, undesired
is removed by behavior or does not happen
at all
– Not the same as punishment
– Not a bad habit being reinforced
– Very powerful method of reinforcement
• Escape conditioning – negative event stops
• Avoidance conditioning – negative event
avoided
Basic Principles of Learning
Punishment
• Consequence of behavior is negative
– Behavior has been punished
– Behavior frequency will decrease
– When appropriately used – ethical and valuable
tool for discouraging undesired behavior
• Physical punishment used by society,
parents, and others
– has dangers
– Raises ethical questions
Basic Principles of Learning
Dangers of Punishment
• Often reinforcing to the punisher
• Often has generalizing effect on the individual
• May lead to a worse problem (learning to dislike
punisher, reacting aggressively towards others)
• Criticism trap – belief that punishment is
ineffective leads to using criticism (criticism
sometimes reinforces negative behavior)
• Punishment may suppress behavior temporarily but
is not long term solution
Basic Principles of Learning
Guideline for Use of Punishment
• Do not use physical punishment
• Punish inappropriate behavior immediately
• Positively reinforce appropriate behavior
• Clarify what behavior is being punished and
why (separate the person from the behavior)
• Do not mix punishment with rewards
• Do not back down once you begin to punish
Basic Principles of Learning
Contrasting Classical and Operant
Conditioning
Classical conditioning
involves
– Association between
two stimuli
– Reflexive, involuntary
behaviors
– UCS making behavior
happen
Operant conditioning
involves
– Association between
response and
consequence
– More complicated
voluntary behaviors
– Reinforcing consequence
occurring only if desired
response is given
Basic Principles of Learning
Stimulus Discrimination and
Generalization
• Stimulus discrimination – deciding
between appropriate and inappropriate
occasions for a response
– Learned by humans and animals
• Stimulus generalization – opposite of
stimulus discrimination
– Similarity of two or more stimuli
Stimulus Generalization and
Reinforcement of a Pigeon’s Pecking
Mean total responses
300
200
100
0
460
480
500
520
540
560
Wavelength
580
600
620
640
Basic Principles of Learning
Extinction: Learning When to Quit
• Extinction
– learned response stops occurring because
original source of learning was removed
• Classical conditioning
– Fear is very difficult to extinguish
– CR extinguished if CS is repeatedly presented
but UCS is no longer paired with it
• Operant conditioning
– Extinction results from change in consequence
Basic Principles of Learning
Extinction
• Differences between classical conditioning
and operant conditioning
• Operant conditioning
– Early stage extinction leads to frustration
– Partial reinforcement effect: schedule and type
of reinforcement greatly influence extinction
• Fastest extinction - continuous reinforcement
– Response prevention: extinguishes avoidance
responses quickly
Basic Principles of Learning
Spontaneous Recovery and Disinhibition
• Course of extinction not smooth – learned
response occurs often before extinction
• Spontaneous recovery
– Response reappears during extinction
• Disinhibition
– Presentation of intense, unrelated stimulus can
cause strength of response to return
– Pavlov: no response is unlearned, just inhibited
Basic Principles of Learning
Theoretical Interpretations of Learning
• Pavlov – Neural connections between brain
areas of learning and responding acquired
• Other psychologists
– Cognition plays central role in learning
• Place learning and cognitive map
• Latent learning
• Insight learning – sudden problem solving
• Learning set – learned to learn insightfully
Monkeys and Impact of Experience
120
Problems
257-312
201-256
101-200
25-32
17-24
9-16
1-8
110
100
90
80
70
60
50
1
2
3
4
Trials
5
6
Basic Principles of Learning
Modeling: Learning by Watching Others
• Bandura – people learn through modeling
– Demonstrates role of cognition in learning
– Cognitive learning occurs by watching before
behavior occurs
• Learn skills
• Use of appropriate behavior in given situation
• Reduce inhibitions
• Learn what behaviors are reinforced
Basic Principles of Learning
Modeling
• Powerful form of learning
• Vicarious reinforcement – likely to imitate
reinforced behaviors
• Vicarious punishment – likely not to
imitate behaviors that are punished
• High status, attractive, likeable, successful
models more likely imitated
– Concerns about television, movies, other media
Basic Principles of Learning
Biological Factors in Learning
• Learning influenced several ways
– Physical ability limitations (ie: fish cannot fly)
– Individual differences – (ie: fear inhibitions)
– Process of evolution – useful fears and survival
mechanisms
• Biological preparedness to learn
• Learned taste aversion ( used on humans
and animals)
Basic Principles of Learning
The End