Operant conditioning is a method of learning through reinforcement and punishment of behaviors. Reinforcements, like rewards, increase the likelihood a behavior will be repeated, while punishments decrease likelihood a behavior will be repeated. Skinner used a technique called shaping to teach behaviors to animals like pigeons by breaking behaviors into small, reinforced steps to build up to a complex behavior. Shaping involves giving reinforcement for closer and closer approximations of the desired behavior until the behavior is learned. The technique was effective for pigeons but not all animals, like raccoons. Shaping can also be used to teach humans complex behaviors by reinforcing successive steps.
2. Operant Conditioning
A method of learning that occurs through reinforcements
and punishments for behavior. We learn to perform
certain behaviors more often because they result in
rewards, and learn to avoid other behaviors because they
result in punishment or adverse consequences.
3. Operant Conditioning
Experiences shape our
future behavior choices,
even if we don’t realize
it is happening.
“Punishment” is something
bad happening to you.
“Reinforcement” is something
good happening. Remember,
“Negative” means something is
taken away, and “Positive” means
something is added to the
environment.
4. Negative Reinforcement
Reinforcement = Do it again!
Negative = Taking something (bad) away
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Positive Reinforcement
Reinforcement = Do it again!
Positive = Adding something (good)
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Positive Punishment
Punishment = Don’t do it again!
Positive = Adding something (bad)
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Negative Punishment
Punishment = Don’t do it again!
Negative = Taking something (good) away
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6. Shaping
To achieve a desired behavior, step-by-step trials are
used to direct the participant towards the end goal.
Skinner noticed that the pigeons in the
skinner box were not accidentally
pushing the button that would release
food. How could he teach the pigeon
that pressing the button would result in
a positive outcome?
In other words: breaking down behavior into small steps,
and giving positive reinforcement along the way can
result in the learning of more complex behaviors.
7. Shaping
Step 1: give the pigeon
food when it turns
toward the button.
Step 3: give the pigeon
food when raises its
head to the height of
the button.
Step 2: give the pigeon
food when it walks
toward the button.
Step 4: give the pigeon
food when taps the
button with its beak.
8. Shaping: What else can we train the bird to do?
“We first give the bird food when it
turns slightly in the direction of the spot
from any part of the cage.This increases
the frequency of such behavior. We then
withhold reinforcement until a slight
movement is made toward the spot.This
again alters the general distribution of
behavior.We continue by reinforcing
positions successively closer to the spot,
then by reinforcing only when the head
is moved slightly forward, and finally only
when the beak actually makes contact
with the spot. ...In this way we can build
complicated operants which would never
appear in the repertoire of the organism
otherwise.”
10. Shaping
Skinner was able to teach pigeons many complex behaviors
- such as telling the difference between different words and
knocking bowling pins over with a miniature bowling ball.
The technique did not work
equally on all animals.
Raccoons, for example,
thought the ball itself was
food, and did not cooperate
in the experiment!
11. Shaping Humans
EXAMPLES
Learning to write. You might begin by
tracing letters. Next, by connecting dots
or dashes. Next, by looking at letters
and copying them below. Finally, by
writing the letters from memory.
Learning to eat with a spoon. First you need
to pick up the spoon. Next you need to put
the spoon in the bowl. Next you need to
scoop the food into the spoon. Next you
need to lift the spoonful out of the bowl.
Finally, you need to put the spoon into your
mouth. Encouragement from parents along
the way can reinforce these movements.