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Learning
A relatively permanent change in an organism’s behavior due to
experience. We learn by association. Our minds naturally connect
events that occur in sequence
Simplest forms of learning – habituation and sensitization. What
are they? Are they really examples of learning?
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Conditioning
Conditioning A basic form of learning
Classical Conditioning
Learning in which response
naturally caused by one stimulus comes to be elicited by a
different, formerly neutral stimulus.
Ivan Pavlov Accidentally discovered classical conditioning.
His experiments on salivation in dogs turned into research
on learning
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Classical Conditioning
Sovfoto
Russian physiologist Ivan Pavlov was the first to scientifically
study classical conditioning. His work provided a basis for later
behaviorists like John Watson and B. F. Skinner
Ivan Pavlov (1849-1936)
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Pavlov’s Experiments
Before conditioning, food (Unconditioned Stimulus, UCS or
US) produces salivation (Unconditioned Response, UR).
However, the tone (neutral stimulus, NS) does not
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Pavlov’s Experiments
During conditioning, the NS (neutral stimulus = tone) and the
US (food) are paired, resulting in salivation (UR). After
conditioning, the NS (now Conditioned Stimulus, CS) elicits
salivation (now Conditioned Response, CR)
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Stimulus Generalization and
Discrimination
The tendency to respond to stimuli similar to the CS is called
generalization
Discrimination is the learned ability to distinguish between a
conditioned stimulus and other stimuli that do not signal an
unconditioned stimulus
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Acquisition (Trials)
Acquisition is the initial stage in classical conditioning in which
an association between a neutral stimulus and an unconditioned
stimulus takes place
1.
2.
3.
In most cases, for conditioning to occur, the neutral
stimulus needs to come before the unconditioned
stimulus (trace conditioning)
The time in between the two stimuli should be about half
second.
Other acquisition pairings – delay, simultaneous,
backward
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Classical Conditioning Applied
Trash Cans and other Objects Altoid
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Extending Pavlov’s Understanding –
Cognitive Processes
Early behaviorists contend that learned behaviors of animals
were mindless associations aka the Contiguity model –
Conditioning will occur whenever NS and UCS are paired
(Pavlov and Watson)
However, later behaviorists suggest that animals learn the
predictability of a stimulus, meaning they learn expectancy
of a stimulus. The Contingency model emphasizes the role
of expectation-NS predicts the UCS (Rescorla and Wagner)
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Biological Factors in Conditioning
Pavlov and Watson believed that laws of learning were
similar for all animals.
However, later behaviorists later suggested that learning is
constrained by an animal’s biology. John Garcia and
Conditioned Taste Aversions. Learning can be constrained
by biological predispositions
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Biological Predispositions
Courtesy of John Garcia
Garcia showed that the duration between the
CS and the US may be long (hours), but yet
still result in conditioning. A biologically
adaptive CS (taste) led to conditioning and not
to others (light or sound). Known as the
Garcia effect or Sauce Bernaise Syndrome
John Garcia
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Classical Conditioning in Humans
• Taste aversions Association between taste of a certain food
and a feeling of nausea.
• How are taste aversions slightly different than classical,
classical conditioning?
– May occur often with only a single pairing
– Pairing may not be close in time
– Speed of learning (role of survival?)
• Preparedness is the notion that humans are predisposed to
develop some phobias because they have biological
survival value
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Applications of Classical Conditioning
to Humans
• The Baby Albert experiment
demonstrated classically conditioned
phobia in humans (John Watson and
Rosalie Raynor) UCS/UCR/NSCS/CR GS Baby Albert
Brown Brothers
• Watson later used conditioning
procedures to develop advertising
campaigns. Father of brand loyalty
and the concept of market niche.
Maxwell House campaign made the
“coffee break” an American custom
John B. Watson
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Classical Conditioning in Humans –
Uses in Behavioral Therapy
Systematic Desensitization (Mary Cover Jones) A
counterconditioning technique that used to treat phobias.
She counterconditioned Watson’s babies. Person learns to
relax in presence of stimulus that used to be upsetting
(progressive relaxation – Wolpe). Also called exposure
therapy. Extreme form is called flooding
Aversive conditioning Associates unpleasant state with
unwanted behavior (like Gustavson!). Antabuse and
alcohol, bell pad method, Kubrick, Other examples?
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Classical v. Operant Conditioning
Classical
conditioning
forms associations between
stimuli (CS and US). It
occurs as an automatic
response to a certain
stimulus
Operant conditioning (or
instrumental) forms an
association
between
behaviors and the resulting
events
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Thorndike’s Experiments
Skinner’s experiments extend Thorndike’s law of effect.
This states that rewarded behavior is likely to occur again
Yale University Library
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Operant Conditioning
• Learning in which an organism’s behavior is followed by a
reinforcer (positive or negative) or punishment
• Organism learns to perform behavior in order to gain a reward
or avoid a punishment
• Reinforcer A stimulus or event that follows a behavior and
makes that behavior more likely to occur again (includes both
positive and negative reinforcers)
• Punisher A stimulus or event that follows a behavior and
makes that behavior less likely to occur again
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Types of Reinforcement
• Positive reinforcer (+)
– Adds something
following a behavior,
making that behavior
more likely to occur
again
– Giving a dog a treat for
fetching a ball
• Negative reinforcer (-)
– Removes something
unpleasant from the
environment following a
behavior, making that
behavior more likely to
occur again
– Taking an aspirin to
relieve a headache
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Concepts in Reinforcement
•
Immediate Reinforcer Occurs instantly after a behavior.
A rat gets a food pellet for a bar press (TV v. studying)
•
Delayed Reinforcer Is delayed in time for a certain
behavior, e.g. a paycheck at the end of a week
•
Continuous Reinforcement Reinforces the desired
response each time it occurs (Rapid learning and rapid
extinction)
•
Partial (Intermittent) Reinforcement Reinforces a
response only part of the time and shows greater
resistance to extinction (ratio and interval)
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Reinforcement Schedules
Fixed-ratio schedule Reinforces a response only after a
specified number of responses. “Pause and run” response
Variable-ratio schedule Reinforces a response after an
unpredictable number of responses. High unpredictability.
(e.g., behaviors like gambling, fishing). Consistently high
rate of response, hard to extinguish
Fixed-interval schedule: Reinforces a response only after
a specified time has elapsed. (quiz Friday, study
Thursday). Response occurs at end in anticipation
Variable-interval schedule: Reinforces a response at
unpredictable time intervals, which produces moderate,
steady responses. (pop quizzes)
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Operant Chamber
The operant chamber (or Skinner box), comes with a bar or
key that an animal manipulates to obtain a reinforcer like
food or water. The bar or key is connected to devices that
record the animal’s response. Skinner
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Shaping
Shaping is the operant conditioning procedure in which
reinforcers guide behavior towards the desired target behavior
through successive approximations
Fred Bavendam/ Peter Arnold, Inc.
Khamis Ramadhan/ Panapress/ Getty Images
A rat shaped to sniff mines. A manatee shaped to discriminate
objects of different shapes, colors and sizes.
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What about the Brelands?
Instinctual drift/biological predispositions?
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Primary & Secondary Reinforcers
Primary Reinforcer An innately
reinforcing stimulus like food or drink
Conditioned
Reinforcer
(or
secondary) A learned reinforcer that
gets its reinforcing power through
association
with
the
primary
reinforcer
Wolfe’s Chimp-O-Mat.
examples?
Other
Discovering Psychology Learning
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Negative Reinforcement
• Negative reinforcement increases the likelihood of a
behavior (or strengthens) by removing or preventing a
stimulus from occurring
– Escape conditioning
– Avoidance conditioning
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Negative Reinforcement
• What is the aversive stimulus and the behavior being
strengthened by its removal? Is the behavior an escape or
avoidance response?
–
–
–
–
–
–
–
–
1. Taking an aspirin to relieve a headache
2. Feigning a stomach ache to stay home from school
3. Smoking in order to relieve anxiety
4. Arriving to class on time to avoid a teacher's glare
5. Leaving the movie theater if a movie is horrible
6. Putting on your seatbelt to stop the buzz
7. Coming home before curfew to avoid trouble
8. Driving the speed limit through Venice
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Negative Reinforcement is NOT
Punishment
• Punishment decreases the occurrence of a behavior (or may)
• Positive punishment (administers aversive stimulus) v.
negative punishment (withdraws a desirable stimulus aka
omission training)
• Effective punishment
– Should occur as soon as possible after the behavior
– Should be sufficient, i.e., strong enough
– Should be certain, occurring every time the behavior does
– Should be consistent and relevant to behavior
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Punishment
Although there is some justification for occasional
punishment (Larzelaere & Baumrind, 2002), it often leads to
negative outcomes
1. Results in unwanted fears
2. Conveys no information to the organism (appropriate
behavior, e.g., only suppresses behavior)
3. Justifies pain to others
4. Causes unwanted behaviors to reappear in its absence
5. Causes anger and aggression towards the agent
6. Causes one unwanted behavior to appear in place of
another
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Skinner’s Legacy
• Skinner provides a vocabulary for
understanding conditioning and reinforcement
and their role in the learning process
• While Skinner accepted inner thought
processes and biological underpinnings, he
discounted them as a means of changing
behavior (a fruitless endeavor). He argued that
behaviors were shaped by external influences
instead of inner thoughts and feelings
• Ascribed nearly all behavior to conditioning.
• Positive,
hopeful
and
helpful
or
reductionistic, dehumanizing and dangerous?
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Role of Motivation
Intrinsic Motivation
The desire to perform a behavior
for its own sake
Extrinsic Motivation
The desire to perform a behavior
due to promised rewards or
threats of punishments
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Seligman and Learned Helplessness
• Learned helplessness
experiments
• Possible model for depression
– Stability and instability
– Internal v. external
– Global v. specific
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Social Learning Theory
• Social learning theory focuses on what we learn from
observing other people (modelling and imitative behavior)
• Bandura's Bobo doll study (1961) indicated that individuals
(children) learn through imitating others who receive rewards
and punishments
– Observational or vicarious learning occurs when we see the
consequences of other people’s behavior
– Vicarious reinforcement or vicarious punishment affects
the willingness of people to perform behaviors they learned
by watching others and subsequent consequences
– Pro-social and anti-social models
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Observational or Social Learning Theory
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Media and Observational Learning
Multiple studies show both
correlation and causal effects
Ron Chapple/ Taxi/ Getty Images
Gentile, et al., (2004) shows
that children in elementary
school who are exposed to
violent television, videos,
and video games express
increased aggression.
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Causes and Effects of Media Violence
• Observational
Learning/Modeling
• Desensitization (psychic
numbing)
• Disinhibition
• Circular effect
• Dangerous world phenomenon
• Increased Arousal theory
• Priming effect
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Challenges to Behaviorism – The Role
of Cognitive Learning
• Evidence of cognitive processes during operant learning
comes from rats during a maze exploration in which they
navigate the maze without an obvious reward (E.C. Tolman’s
rat mazes). Rats develop cognitive maps, or mental
representations, of the layout of the maze.
• Such cognitive maps are based on latent learning, which
becomes apparent when an incentive is given (Tolman &
Honzik, 1930).
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Cognitive Learning
Insight and Aha Experience
• Insight is when learning seems to occur in a sudden “flash” as
elements of a situation come together. Kohler experiments
and “Aha” experiences
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Biological and Evolutionary Bases for
Learning
• Possible role of mirror neurons
• Long-term potentiation changes at neural level
• Kandel’s aplysia studies (classical conditioning - ltp and
neuromodulators)
• Evolutionary basis for learning. Imitation onset, aversions…
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