Transcript File

Learning
Geddes
2014
Classical Conditioning
• Ivan Pavlov
• Studied Digestion of
Dogs.
• Dogs would salivate
before they were
given food (triggered
by sounds, lights
etc…)
• Dogs must have
LEARNED to salivate.
Click above to see about Pavlov
Classical Conditioning
• This is passive learning
(automatic…learner does
NOT have to think).
• First thing you need is an
unconditional relationship.
• Unconditional Stimulus
(UCS)- something that
elicits a natural, reflexive
response.
• Unconditional Response
(UCR)- response to the
UCS.
Classical Conditioning
• Next you find a neutral stimulus (something
that by itself elicits no response).
• You present the stimulus with the UCS a
whole bunch of times.
Classical Conditioning
• After a while, the
body begins to link
together the neutral
stimulus with the
UCS.
• Acquisition
Classical Conditioning
• We know learning takes
places when the
previously neutral
stimulus elicits a
response.
• At this point the
neutral stimulus is
called the conditioned
stimulus (CS) and the
unconditional response
becomes the
conditioned response
(CR).
Classical Conditioning
• We know learning exists
because the CS is linked to
the UCS.
• This is called
ACQUISITION.
• Acquisition does not last
forever.
• The moment the CS is no
longer associated with the
UCS, we have
EXTINCTION.
• SPONTANEOUS
RECOVERY: Sometimes,
after extinction, the CR
still randomly appears after
the CS is presented.
Classical Conditioning
Strength
of CR
Acquisition
(CS+UCS)
Extinction
(CS alone)
Spontaneous
recovery of
CR
Extinction
(CS alone)
Pause
Generalization and Discrimination
Generalization
• Something is so similar
to the CS that you get a
CR.
Discrimination
• Something so different
to the CS so you do not
get a CR.
Does Timing matter?
• The CS should come right before the US!
Little Albert
• Conditioned by Watson to fear rats
• Are all of our fears conditioned?
• No one knows what happened to Little Albert
Classical Conditioning--Examples
• Fred has a fluffy down pillow with some of the
down sticking out of the fabric. When he first
tries out the pillow, a piece of down tickles his
nose and he sneezes. This happens every time he
goes to bed. Soon he sneezes every time he lays
down on any kind of pillow
• US___________________ UR_______________
NS/CS________________ CR_______________
Examples
• It is springtime and the pollen from the
flowers causes you to sneeze. Soon you are
sneezing every time you see a flower.
US___________________
UR_______________
NS/CS________________
CR_______________
Examples
• People receiving chemotherapy often vomit
during or shortly after the procedure. After
several chemotherapy sessions, people begin
feeling sick at the sight of the treatment
room.
• US___________________
UR_______________
NS/CS________________
CR_______________
Examples
• Your significant other often yells at you and
makes you feel bad. Pretty soon you can’t stand
the look of that person and end the
relationship. You meet another person who
looks like your ex. Although they seem nice, you
find yourself feeling bad every time you are
around them.
• US___________________ UR_______________
NS/CS________________ CR_______________
Examples
• You meet a new person who is an excellent
cook. After a few superb meals you find
yourself liking that person very much.
• US___________________
UR_______________
NS/CS________________
CR_______________
Learned Taste Aversions
• When it comes to
food being paired
with sickness, the
conditioning is
incredible strong.
• Even when food and
sickness are hours
apart.
• Food must be salient
(noticeable.)
Garcia and Koelling Study
• Studied rats and
how they make
associations.
• Some associations
seem to be adaptive.
CS
UCS
Learned Response
Loud Noise
Shock
Fear
Loud Noise
Radiation (nausea)
Nothing
Sweet Water
Shock
Nothing
Sweet Water
Radiation (nausea)
Avoid Water
Operant Conditioning
The Learner is NOT passive.
Learning based on consequence!!!
Edward Thorndike—Law of Effect
• Behavior
followed
by a
reward
will
increase
B.F. Skinner
• The King of Operant
Conditioning.
• Nurture guy through
and through.
• Used a Skinner Box
(Operant
Conditioning
Chamber) to prove
his concepts.
Life is a Skinner Box!
Reinforcement
• Anything that follows a behavior, making the
behavior more likely to occur (strengthens
the behavior)
• Two types:
– Positive
• The addition of something pleasant
– Negative
• The removal of something unpleasant
Reinforcement
• Shaping Behavior through Positive
Reinforcement
Positive or Negative?
Putting your seatbelt on.
Faking sick to
avoid AP Psych
class.
Studying for a test.
Having a headache and
taking an aspirin.
Breaking out
of jail.
Getting a kiss
for doing the
dishes.
Punishment
Anything that follows a
behavior and makes it
less likely to happen in
the future.
Positive Punishment
• Addition of something
unpleasant.
Negative Punishment
• Removal of something
pleasant.
Punishment works best
when it is done
immediately after the
behavior
Punishment can’t be used
in isolation!
Punishment is NOT Negative
Reinforcement!
• This is the most common mistake made when
working with examples of operant
conditioning.
• The 1st thing to decide is whether a behavior is
increasing (reinforcement) or decreasing
(punishment).
• Then decide whether you’ve added something
(positive) or taken something away (negative)
Positive Punishment and Negative
Reinforcement
• Big Bang Theory—Reinforcement and
Punishment
Negative Reinforcement
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Taking aspirin to relieve a headache
Hurrying home in the winter to get out of the cold
Giving in to a dog’s begging
Fanning oneself to escape the heat
Leaving a movie theater if the movie is bad
Smoking in order to relieve anxiety
Following prison rules in order to be released from
confinement
Faking a stomachache in order to avoid school
Putting on a car safety belt to stop an irritating buzz
Turning down the volume of a very loud radio
Putting up an umbrella to escape the rain
Saying “uncle” to stop being beaten
Shaping
• Do we just wait for
the desired
behavior and then
reinforce it?
• NO—we use a
process called
shaping:
– Reinforcing
successive
approximations of
a behavior until
you get the desired
result.
Chaining
• Subjects are taught a number of responses in
order to receive a reward
• Like learning a dance routine
Primary v. Secondary Reinforcers
Primary Reinforcer
• Things that are
naturally rewarding.
Secondary Reinforcer
• Things we have learned to
value.
• Money is a special
secondary reinforcer
called a generalized
reinforcer (because it
can be traded for just
about anything)
Token Economy
• Every time a desired
behavior is performed,
a token is given.
• They can trade tokens
in for a variety of
prizes (reinforcers)
• Used in homes, prisons,
mental institutions and
schools.
Choosing Reinforcers
• Humans aren’t as easy to reinforce as animals!
• What is reinforcing for me (steak) probably
wouldn’t be a good reinforcer for a vegetarian.
• Sometimes what we think is punishment can
actually be a reinforcement, as in the case of a
neglected kid
Reinforcement Schedules
How often should you
give the reinforcer?
• Every time? or just
some of the times
you see the
behavior?
Continuous v. Partial
Reinforcement
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Continuous
Reinforce the behavior
EVERYTIME the behavior
is exhibited.
Usually done when the
subject is first learning
to make the association.
Acquisition comes really
fast.
But so does extinction.
Partial
• Reinforce the behavior
only SOME of the times
it is exhibited.
• Acquisition comes more
slowly.
• But is more resistant to
extinction.
• FOUR types of Partial
Reinforcement
schedules.
Ratio Schedules
Fixed Ratio
• Provides a
reinforcement after a
SET number of
responses.
– Like collecting coins in
Super Mario Bros.
Variable Ratio
• Provides a
reinforcement after a
RANDOM number of
responses.
• Very resistant to
extinction.
– Like playing a slot
machine
Interval Schedules
Fixed Interval
Variable Interval
• Requires a SET amount
of time to elapse before
giving the
reinforcement.
• Requires a RANDOM
amount of time to elapse
before giving the
reinforcement.
• Very hard to get
acquisition but also very
resistant to extinction.
– Like waiting for the bus.
– Like checking your email
Fixed Interval: She gets a
manicure for every 7 days she
stays on her diet.
Observational Learning
• Albert Bandura and his
BoBo Doll
• We learn through
modeling behavior from
others.
• Observational learning +
Operant Conditioning =
Social Learning Theory
Observational Learning
• MIRROR NEURONS—they fire when I do
something or if I see you do something.
(biological basis for observational learning)
• Mirror Neurons
Observational Learning-Research
• Homicide rate doubled between 1957
and 1974 (when TV was introduced and
spreading)
• TV introduced in 1975 to South Africa.
Homicide rate then doubles
• School children with heavy exposure to
violent TV get into more fights
• DOES VIOLENT TV CAUSE
VIOLENCE?
Latent Learning
Edward Toleman
Rat maze experiment.
Latent means hidden.
Rats developed a
cognitive map
• Sometimes learning is
not immediately
evident.
• Rats needed a reason
to display what they
had learned.
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Intrinsic vs. Extrinsic Motivation
• Intrinsic Motivation—the desire to perform
some behavior for its own sake.
• Extrinsic Motivation—performing behaviors to
receive external rewards or to avoid
punishment
• Think about the work you do in school? What
is the main motivational factor?
Insight Learning
• Learning through the “ah-ha!” experience