Transcript 3.1 Learning - Coshocton City Schools

AP Psychology
3.1 Learning
Learning
• A lasting change in behavior or mental
processes as the result of an experience
– Behavior can be observed
– Mental processes are more difficult to study
Instincts vs. Learning
Instincts
• Instincts are unlearned
behaviors due to
evolutionary programming
that are found in almost all
members of a species
• Example…bears hibernate,
geese migrate, salmon swim
upstream to spawn
• Humans…debated, but…
– Grasping reflex, sucking
reflex, pull hand away from
fire, blinking
Learning
• Represents a significant
evolutionary advance over
instinctive behavior
• Enables humans to acquire
new knowledge that can be
transferred from one
generation to another
Classical Conditioning
• Ivan Pavlov (1849-1936)
• Russian (later Soviet) physiologist who was
awarded a Nobel Prize in 1904 for his research
on the digestive system of dogs
• While conducting experiments…Pavlov
noticed that his dogs tended to salivate before
food was actually delivered to their mouths
Classical Conditioning
• Spent 3 decades…532 experiments to studying
classical conditioning
• Discovered classical conditioning (because first
to be extensively studied in psych)
• Condition = learned
• Elicit = cause / produce / bring forth
5 Components of Classical
Conditioning
1. Unconditioned Stimulus (UCS) (US)
- natural stimulus that reflexively elicits a
response without the need for prior learning
- Pavlov used food as the US because it
produced naturally occurring salivation reflex
- Unlearned stimulus = automatic
5 Components of Classical
Conditioning
2. Unconditioned Response (UCR) (UR)
- Unlearned response that is elicited by an US
- In Pavlov’s experiments, salivation was the UR
5 Components of Classical
Conditioning
3. Neutral Stimulus (NS)
- Any stimulus that produces no conditioned
response prior to learning
- In Pavlov’s experiments a ringing bell was
originally a neutral stimulus.
5 Components of Classical
Conditioning
4. Conditioned Stimulus (CS)
- The CS was originally the NS.
- When systematically paired with the US, the
NS becomes a conditioned (learned) stimulus
as it gains the power to cause a response
- In Pavlov’s experiments, the ringing bell
became a CS when it began to produce the
same salivating response that the food once
produced
5 Components of Classical
Conditioning
5. Conditioned Response (CR)
- A CR is a learned response elicited by the CS
- Pavlov called the process by which a CS elicits a
CR “acquisition”
- In Pavlov’s experiments, he paired the ringing bell
with food. Originally a NS, the ringing bell
became a CS when the dog reacted with a CR by
salivating
- The dog’s salivation was both an UR and CR
- **CC is most efficient when the CS immediately
precedes the US**
Example of CC
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Toilet flush and shower
US – hot water
UR – jumping back
NS – originally the toilet flush
CS – becomes the toilet flush
CR – jumping back
John B. Watson – “Little Albert”
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Taught baby Albert to fear a rat
NS - Rat
Reflex: US (loud noise)  UR (cry)
Acquisition: NS + US  UR
Acq. Demonstrated:
– CS (rat)  CR (cry)
• Shows how phobias and human emotions
develop
Extinction
• Gradual weakening of a conditioned behavior
when the CS is not followed by the US
• Example…Pavlov presented the ringing bell
without food --- as a result, the ringing bell
gradually lost its power to elicit the CR of
salivation
Spontaneous Recovery
• The reappearance of an extinguished CR after
a time delay
• Example…Pavlov discovered that after a
period of time, his dogs began salivating when
they heard the sound of the bell **Note – the
CR reappears at a lower intensity
• This shows how difficult it can be to eliminate
a CR
Generalization
• Occurs when stimuli that are similar to the
original stimulus also elicit the CR (when a
new stimulus was not paired with the US
• Example…Pavlov found that a dog conditioned
to a low-pitched tone would also respond to a
high-pitched tone
Discrimination
• Ability to distinguish between two similar
stimuli
• Example…students have learned different
responses to the sound of bells in the
classroom, cell phones, and front doors
• Example…gardeners demonstrate
discrimination when they respond differently
to weeds and to flowers
Generalization/Discrimination
• Example…
• A young boy is bitten by his neighbors dog
• He runs away when he sees any neighborhood
dog (Generalization)
• He still enjoys playing with his family's pet
collie (Discrimination)
Higher-order conditioning
• Aka – second-order conditioning
• A CS from one learning trial is paired with a new
• The new US becomes the new CS capable of
eliciting the CR even though it has never been
paired with the US
• Example… Pavlov CC a dog to salivate to the
sound of a ticking metronome . He then paired
the metronome with a black square. After several
pairings, the black square produce salivation even
though it had never been paired with food.
A rat has already been conditioned to associate the blue stick with a cat odor(US). A red light is
flashed on before the blue stick is placed in its cage. The rat displays a second-order conditioned
response when just the red tight is turned on.
Taste Aversion
• A CC dislike for and avoidance of a particular
food that develops when an organism
becomes ill after eating the food
• Many people have experienced vivid examples
of taster aversion
Taste Aversion
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Aka – Aversive Conditioning
NS: food
Reflex: US (stomach virus) UR (vomiting)
Acquisition: NS + US  UR
Acq. Demonstrated:
– CS (food)  CR (vomiting – sick)
Taste Aversion
• John Garcia experiments (1917)
• Conducted experiments to demonstrate that
taste aversions could be produced in
laboratory rats
• NS (saccharin-flavored water)
• US (drug) -> UR (gastrointestinal distress)
• After recovering from illness, the rats refused
to drink the flavored water (taste aversion)
Taste Aversion
• Garcia’s findings challenged two basic
principles of CC
– 1. conditioning only required a single pairing
– 2. conditioning does not always need to be
separated by seconds – he separated the stimuli
by several hours
**demonstrated there are biological constraints on
conditioning!
Taste Aversion
• Example – Wolves and Sheep
Operant Conditioning
• Limitations on Classical
Conditioning…
– CC focuses on existing
reflexive behaviors that
are automatically
elicited
– Learning, however,
involves new behaviors
or voluntary actions that
classical conditioning
cannot explain
Edward L. Thorndike
• His studies on baby chicks and cats were the
first systematic investigation of animal
learning
• Focused on how voluntary behaviors are
influenced by their consequences
Thorndike and the Law of Effect
• Responses that lead to satisfying outcomes
are more likely to be repeated
• Responses followed by unpleasant outcomes
are less likely to be repeated
Thorndike – “Cat in a Puzzle Box”
BF Skinner
• Behaviorist who believed that psychologists
should focus on observable behavior that
could be objectively measured and verified
Skinner and Operant Conditioning
• Formulated the principle of Operant
Conditioning
• OC – any “active behavior that operated upon
the environment to generate consequences”
• OC is a learning process in which behavior is
shaped and maintained by consequences
(rewards or punishments) that follow a
response
• CC (SR) / OC (RS)
Skinner Box
• The box is a chamber that includes at least one
lever, bar, or key that the animal can manipulate.
• When the lever is pressed, food, water, or some
other type of reinforcement might be dispensed.
• Other stimuli can also be presented including
lights, sounds, and images.
• In some instances, the floor of the chamber may
be electrified
Skinner Box
Operant Conditioning: Reinforcement
• Reinforcement occurs when a stimulus
(reinforcer) follows an active behavior or
response
• The reinforcer increases the probability that
the behavior or response will be repeated
Positive Reinforcement
• Behavior is followed by the addition of
reinforcing stimulus
• Stimulus increases the probability that the
response will occur again
• NOTE – positive does not mean “good” or
“desirable”
• Positive like a “+” sign
– Indicates a response is strengthened because
something is added
Examples of “+” Reinforcement
• Flawless performance is school play (the
operant) / your drama coach applauds and
exclaims “Bravo!” reinforcing stimulus)
• You earn a “A” on an AP Psychology Test (the
operant) / your teacher writes you a letter
(reinforcing stimulus))
Negative Reinforcement
• Behavior or response is followed by the
removal of an adverse stimulus
• NOTE - negative does not mean “bad” or
“undesirable”
• Negative like a “-” sign
– Indicates that a response is strengthened because
something is subtracted or removed
Examples of “-” Reinforcement
• You take out the garbage (the operant) to avoid
your mother’s repeated nagging (aversive
stimulus)
• You put on sunscreen (the operant) to avoid
getting sunburned (aversive stimulus)
• You give your little brother a candy bar (the
operant) to prevent him from crying (aversive
stimulus)
• Your little sister is crying (the operant), you hug
her and she stops crying (aversive stimulus)
Premack Principle
• David Premack
• Stated that the
opportunity to engage
in a preferred activity
can be used to reinforce
a less-preferred activity
Premack Principle Examples
• You enjoy playing video • You enjoy eating ice
games far more than
cream for dessert far
studying for the ACT.
more than eating
vegetables.
• Knowing this, you tie
the less-preferred
• Knowing this, your
activity (studying for the
mother ties the lessACT) to your preferred
desired activity (eating
activity (playing video
veggies) to your
games)
preferred activity
(eating ice cream)
Types of Reinforcers
• Primary Reinforcers
– Naturally reinforcing for a species
– Ex…food, water, shelter, sex
• Secondary Reinforcers
– Gains effectiveness by a learned association with
primary reinforcers
– Ex…money
Types of Reinforcers
• Token Economy
– Individuals rewarded with tokens that can act as
secondary reinforcers.
– The tokens can be redeemed for rewards and
priveledges
– Elementary Teachers – gold stars
Continuous Reinforcement
• Reinforcement schedule in which all correct
responses are reinforced
• Responses extinguish faster when they are
learned through this
Shaping
• Technique of strengthening behavior by
reinforcing successive approximations of a
behavior until the entire correct routine is
displayed
• Used by athletic coaches and animal trainers
Intermittent Reinforcement
• Rewarding of some, but not all, correct
responses
• Advantages
– Most efficient way to maintain behaviors already
learned
– Are very resistant to extinction
– Example – Gambling (very difficult habit to
extinguish)
Schedule of Reinforcement
Ratio Schedules
• Based on number of
responses
Interval Schedules
• Based on responses made
within a certain time period
• Fixed ratio
• Variable ration
• Fixed interval
• Variable interval
Fixed Ratio Schedule
• Reinforcement occurs
after a predetermined set
of responses
– Produce high response
rates (brief drop-off after
reinforcement)
• Examples…
– an employer pays workers
every three baskets of fruit
– Mario Bros – 100 coins =
life
Variable Ratio Schedule
• Reinforcement is unpredictable because the
ratio varies
• High response rates and resistant to
extinction
• Examples…
– Casino slot machines
– Golf
– Door-to-door salesman
Fixed Interval Schedule
• Reinforcement occurs
after a predetermined
time has elapsed
– Moderate response rates
followed by a flurry of
activity near the end of
each interval
• Examples…
– Employers paying
employees every two
weeks
– Teachers who give a quiz
every week
– Baking a cake
Variable Interval Schedule
• Reinforcement occurs
unpredictably since the
time interval varies
– Produce low but steady
response rates
• Examples…
– Teachers and pop
quizzes
– Fishing
– Parent attending to
children crying
Punishment
• Process by which a
behavior is followed by an
aversive consequence
that decreases the
likelihood the behavior
being repeated.
• Is NOT the same as
reinforcement
– Punishment decreases the
likelihood of a behavior
– Reinforcement increases
the likelihood of a behavior
Positive Punishment
• Application or adding of an aversive stimulus
after a response
• Examples…
– You arrive late for work (operant) you are docked
pay (aversive stimulus)
– You show off your knowledge by answering all the
teacher’s questions (operant) a popular girl makes
a snide remark about you (aversive stimulus)
Negative Punishment (Omission Training)
• Removal or subtraction of a reinforcing stimulus
(privilege)
• NOT negative reinforcement!
– Negative punishment makes a behavior less likely to
happen
– Negative reinforcement makes a behavior more likely to
happen
• Examples…
– You arrive at work late (operant) and are sent home
without pay (loss of reinforcing stimulus)
– You show off your knowledge by answering all the
teacher’s questions (operant) and the popular girl doesn’t
invite you to her party (loss of reinforcing stimulus)
– Person who was caught driving while intoxicated also loses
her driver’s license
Drawbacks of Punishment
• Can produce undesirable results (fear, hostility,
aggression)
• Often produces temporary change
• Can produce Learned Helplessness
– Occurs when a learner feels that it is impossible to
escape punishment
– Leads to passive feeling hopelessness that may lead to
depression
• Example…
– A student is doing poorly in AP Psych
– “No matter what I do, I’m going to fail”
Effective Use of Punishment
• Should be delivered immediately after the
offensive behavior
• Should be certain
• Should be limited and sufficient so that it “fits
the crime”
• Should focus on the behavior, not the
character, or the offender
Comparing CC and OC
Classical Conditioning
• Pioneers
– Pavlov and Watson
• Types of Behavior
– Involuntary responses
• Timing of Stimuli
– Precedes the response
– SR
• Use of Rewards/Punishment
– Does not use
Operant Conditioning
• Pioneers
– Thorndike and Skinner
• Types of Behavior
– Voluntary responses
• Timing of Stimuli
– Follows the response
– RS
• Use of Rewards/Punishment
– Based on