Transcript Learning - TeacherWeb

Learning
Learning seems to be one process
that many people take for granted but
know very little about. So, how do we
learn?
Basically, we learn through
associations. If something pleasant
happens as the direct result of one of
your actions, you are more likely to
associate positive feelings with that
action, and thus, repeat it.
CLASSICAL CONDITIONING
Ivan Pavlov was a Russian
physiologist studying digestion.
The dogs would begin to salivate
when they would hear the clinking of
the metal trays, or when the door
would open because they came to
associate that with being fed. He
theorizied that they would salivate
with any unrelated stimulus, if
conditioned. He chose a bell.
The four components of classical
conditioning:
Unconditioned Stimulus (US) – causes a
response that is automatic, not learned.
Unconditioned Response (UR) – the
response to the US.
Conditioned Stimulus (CS) – the originally
neutral stimulus that through conditioning,
gains the power to cause the response.
 Conditioned Response (CR) – the
response to the CS.
The whole object in classical
conditioning is to get your subject to
associate something (anything!) with
the UCS.
In Pavlov’s experiment, the UCS was
the food and the UCR was the
salivation.
Pavlov took a bell, which at first
meant nothing to the dogs (neutral
stimulus), and after many repetitions
conditioned the dogs to associate the
bell with the food.
Now here is the important part. Each
time Pavlov gives the dog food after
the bell, the bell remains a neutral
stimulus.
Once Pavlov rings the bell and does
NOT give the food and the dogs
salivate, the bell becomes what we
call a conditioned stimulus (CS)
and the salivation becomes a
conditioned response (CR).
They are called conditioned
because conditioned means
learned and the dogs have
learned to link the bell and the
food together, it is NOT
unlearned or unconditional.
Classical conditioning helps
organisms adapt to the
surrounding environment.
Extinction is the procedure for
reversing the learning that has taken
place through classical conditioning.
It occurs as the CS loses its power to
trigger a CR.
An extinguished response is not gone
forever. Organisms sometimes
display responses that were
extinguished earlier. The recovered
response is weaker than the original
one and it can be extinguished more
easily.
The linking of the US and CS is called
acquisition and is the goal of classical
conditioning.
Even after extinction, acquisition can
come back at random times even
years later. This is called
spontaneous recovery.
Generalization is when a stimuli is so
close to the CS that it still causes the
CR.
Pavlov was not a psychologist and
limited his studies to animals. It was
not until American psychologist John
Watson conducted his studies on a
baby orphan named Albert that
classical conditioning was used to
actually change a human's behavior.
Watson took an eleven-month-old
orphan, Albert, and gave him pet
white rat. Albert loved the rat and
spent much of the day cuddling with
it.
Then Watson banged some pots
loudly behind Albert while he reached
for the rat. It made the baby cry.
 The loud noise is the US and Albert's
fear is the UR.
After many trials Albert began to
associate the rat with the loud banging
(acquisition).
 Then Watson would bring in the rat
without the loud banging. Predictably,
Albert started to cry when he saw the
white rat because he associated it with
the loud noises.
Albert also cried when Watson brought
in a white bunny or anything that
resembled the rat (generalization).
Because of generalization, stimuli that are
similar to naturally disgusting or appealing
objects will, by association, evoke some
disgust or liking. (Normally desirable
foods like fudge are unappealing when
shaped like dog feces!!)
Discrimination is the learned ability to
distinguish between a conditioned stimulus
and other irrelevant stimuli. (A pit bull dog
racing toward you might send you into a
panic, a golden retriever probably won’t.)
OPERANT CONDITIONING
Operant Conditioning is the concept
that you can change someone’s
behavior by giving them rewards or
by punishing them.
Unlike classical conditioning in which
the learner is passive, in operant
conditioning the learner plays an
active part in the changes in
behavior. This field was started by
Edwin Thorndike.
Thorndike discovered that cats learn
faster if they are rewarded for their
behavior. He called this idea the law
of effect - if the consequences of a
behavior are pleasant, the behavior
will likely increase.
He also stated that is the
consequences of a behavior are
unpleasant, the behavior will not likely
increase- and he called this whole
idea, instrumental learning.
B.F. Skinner actually coined the term
operant conditioning and started this
whole school by inventing the first operant
conditioning chamber, otherwise known as
the Skinner Box.
A Skinner box is used to train animals and
usually has a way to deliver food to an
animal and a lever to press or disk to peck
in order to get the food.
The food is called a reinforcer, and the
process of giving the food is called
reinforcement. A reinforcer is anything
likely to increase a behavior. There are
two types of reinforcement; positive and
negative.
A positive reinforcement strengthens
a response by presenting a typically
pleasurable stimulus after a
response. (A good grade on your test
after studying.)
A negative reinforcement strengthens
a response by reducing or removing
an undesirable stimulus. (Pressing
the snooze button stops the annoying
sound of the alarm clock.)
 We can also change behaviors by using
unpleasant consequences called
punishments. It is important to realize that
punishment work better to stop behaviors
rather than increase them. There are two
types of learning that comes from
punishment:
 Escape learning: allows one to terminate an
aversive stimulus. If you hate psychology
class you will be disruptive so I will kick you
out.
 Avoidance learning: You hate psychology
class so you simply learn to skip.
Whether we are talking about positive or
negative reinforcement, they both fall into
two main reinforcer categories:
Primary reinforcer: things that are in
themselves rewarding. (Food, water, rest)
Secondary reinforcer: things we have
learned to value such as praise, or the big
one MONEY. Money can be traded in for
anything and we constantly increase
behaviors for money. (But if you think
about it, do you really want money? No,
you want what money can buy.)
 Reinforcement Schedules
 Fixed-Ratio Schedule: provides the
reinforcement after a set number of responses.
 Variable-Ratio Schedule: provide the
reinforcement after a random number of
responses.
 Fixed-Interval Schedule: a fixed amount of time
passes before the reinforcement is given.
 Variable- Interval Schedule: a random amount
of time passes before the reinforcement is
given.
 Variable schedules (both ratio and interval) are
more resistant to extinction but also more
difficult to acquire acquisition.
BF Skinner used both positive and
negative reinforcements (he was not really
into punishments) to change the behavior
of both pigeons and rats.
He did it is small successive steps that he
called shaping. For example, let’s say
you want to teach your dog to go fetch
your slippers from the closet and you
wanted to use positive reinforcement to do
so. You would first give your dog a treat
when he goes to your closet (that may
take a couple of days).
Then you would reinforce him again
when he picks up your slippers. Then
you give him a treat once again when
he brings them to your feet.
The idea is that reinforcing all of
these small actions is more effective
than doing the whole process at once;
thus you are shaping the dogs
behavior.
Observational learning, also known
as modeling, was studied a great
deal by a scientist named Albert
Bandura. He believed that many of
us learn through copying others.
Modeling is said to have two
components, observation and
imitation.
Bandura set up a very famous
experiment called the Bobo Doll
experiment to prove his idea that
people observe others and try to
imitate that behavior.
He had children watch a video of a
man pummeling and abusing a plastic
clown doll named Bobo.
Next, the children were led into a
room with many appealing toys, but
were told that they could not touch
them, which made them angry and
frustrated.
Then, they were led into another
room full of Bobo dolls which they
were allowed to touch. An
overwhelming 88% of kids initiated
aggressive behavior towards the
dolls, as they had observed the man
in the video doing.
Latent learning is learning that
becomes obvious only once a
reinforcement is given for
demonstrating it.
Edward Tolman studied latent
learning by using rats and showing us
that learning can occur but may not
be immediately evident.
Tolman had three groups of rats run
through a maze on a series of
trials. One group (Group A) got a
reward each time it completed the
maze, and the performance of these
rats improved steadily over time.
Another group of rats (Group B) never
got a reward, and their performance
improved only slightly over the course
of the experiment.
A third group of rats (Group C) was
not rewarded during the first half of
the experiment, but was given a
reward during the second half of the
experiment.
Not surprisingly, during the first half of
the trials, Group C was very similar to
the group that never received a
reward (Group B).
The interesting finding, however, was
that Group C's performance improved
dramatically and suddenly once it
began to be rewarded for finishing the
maze.
In fact, Group C's performance
almost caught up to Group A's
performance even though Group A
was rewarded through the whole
experiment.
Tolman believed that these rats must
have learned their way around the maze
during the first half of the experiment,
but did not improve because they had
no reason to run the maze quickly.
He believed that their dramatic
improvement in maze-running time was
due to latent learning. He suggested
they made a mental representation, or
cognitive map, of the maze during the
first half of the experiment and
displayed this knowledge once they
were rewarded.
Unnecessary rewards sometimes carry
hidden costs, however. Excessive
rewards can undermine intrinsic
motivation, or the desire to perform
effectively for its own sake.
Extrinsic motivation is the desire to
behave in certain ways to receive external
rewards or avoid punishment.
Rewards should be used neither to bribe,
nor to control, but to signal a job well
done.