Transcript Operant Conditioning

Welcome!
• Please write down your homework:
– Test next class. Ch. 8 and all review chapters
– Notecards due next class
Operant Conditioning
Introduction
Classical Conditioning= an organism
associates different stimuli that it does not
control.
Operant Conditioning= the organism
associates its behaviors with
consequences. Behaviors followed by
reinforcements increase; those followed by
punishers decrease.
Operant means…
….Explain and train
Operant Conditioning
• A type of learning in which
responses can be controlled by
their consequences
i.e. rewards
or
punishments
Reward vs. Punishment
Reward = more likely
behavior will repeat
Punishment = less likely to
repeat behaviors
Behavior
• Respondent Behavior
– Behavior that occurs as
an automatic response
to some stimulus
Ex: food when hungry;
water when thirsty
• Operant Behavior
– The act operates on
the environment to
produce rewarding or
punishing stimuli
Ex: good grades =
MONEY; bad grades =
grounded
Important People in
Operant Conditioning
B.F. Skinner
Radical Behaviorism
Skinner Box
Edward
Thorndike
Law of Effect
Puzzle Box
Skinner
• Operant Chamber– “Skinner Box”
– Soundproof
– Bar or key that an animal presses or pecks to
release a rewards of food or water
– Device that records these responses
• Shaping- Procedure in which reinforcers (like food)
gradually guide an animal’s actions toward a
desired behavior
Edward L. Thorndike
• Law of Effect:
– Rewarded behavior is likely to reoccur
– Puzzle Box
Operant Conditioning Chamber
Skinner Box
Puzzle Box
Two important concepts used in Operant Conditioning
• Reinforcer - (Positive and Negative)
– A stimulus or event that increases the odds of repeating the
behavior that led to it
I give my kids money when they clean their room…this stimulus increases the
odds they will do it again
• Punisher
– A stimulus or event that functions to decreases the odds of
repeating the behavior that lead to
I spank my kids when they throw food at the dinner table…this event
decreases the odds they will do it again
Remember…
– It is often the learner that determines if something is a
reinforcement or punishment
– This is called the Premack Principle
Example: I might give Ryan broccoli after he did a chore and if he likes it he will do more
chores or I might give Ryan broccoli after he did a chore and he may never do that chore
again. My feelings toward broccoli make no difference
Reinforcer
Anything likely to increase a behavior
Two Types of Reinforcement:
Positive and Negative
Positive Reinforcement
• Something desirable is added to the
environment and this encourages (reinforces)
behavior
– Behaviors are strengthened when they are followed
by the introduction of a stimulus
A
Negative Reinforcement
• Something undesirable is subtracted from the
environment and this encourages (reinforces)
behavior
– NR are aversive stimuli such as loud noise, cold, pain, or
nagging
• We are more likely to repeat behaviors that lead to their removal
– Example
•
•
•
•
Say I have a headache
The NR is the pain of the headache
I take aspirin and the headache goes away
Headache pain (stimulus) - - aspirin (response) - - consequence
(headache gone)
• I will take aspirin again because it removed something unpleasant
So…positive and negative do not mean good or bad.
Instead, positive means adding a stimulus, and
negative means removing a stimulus.
Types of Reinforcers
Types of Reinforcers
• Primary Reinforcers- reinforcements that
happen naturally; not learned (i.e. getting food
when hungry, taking your hand off a burning
stove to relieve pain)
• Conditioned Reinforcers- (secondary
reinforcers) are learned. (i.e. if a rat in Skinner’s
box learns that when a light signal goes off it
signals food, the light becomes on the
secondary reinforcer
Primary Reinforcer
• Things that are in themselves rewarding and
satisfy biological needs
• Like food, warmth, or water
Secondary (or Conditioned)
Reinforcer
• Something that you have learned to value
through classical conditioning
– Money, fines or grades
• Secondary reinforcers can loose their effectiveness
Reinforcement
Schedules
The pattern (schedule) in which
reinforcement (reward or
punishment) is given.
These schedules influence learning
Continuous
Reinforcement
• Reinforcing the desired response every
time it occurs.
– Example – vending machine
Quick Acquisition
Quick Extinction
Partial Reinforcement
• Reinforcing a response only part of the time.
– slot machine
– You don’t expect to win every
time but hope to win sometime
– The acquisition process is slower, but…
– Greater resistance to extinction.
• 4 different partial reinforcement schedules
– Two focus on time between reinforcement
(interval
schedule)
– Two focus on number of responses between
reinforcement (ratio
schedule)
Fixed-Interval Schedule
• Reinforcement of a behavior after a
specified or fixed time (interval) has
passed.
• You get paid every two weeks
• A worker gets a bonus once a year
– After receiving a reward (a reinforcement)
the worker has to wait one year for another
reward (fixed interval)
Variable-interval Schedule
• Reinforcement of a behavior
at unpredictable (variable)
time intervals.
• You don’t know when the
reinforcement is coming so
you keep trying or have to be
prepared to take action
Pop Quizzes
Fixed-ratio Schedules
• Reinforcement of a behavior only after a
specified (fixed) number of responses
• Movie rentals that say rent 5 get one free
• A worker gets a bonus after every three
items he sells
Variable-ratio Schedule
• Reinforcement of a behavior after an
unpredictable (variable) number of
responses.
– Working on sales commission
• Sometimes called the gambler’s schedule
– Back to the lottery…
– You don’t know when you will win but you do
know the more you buy the better your chances
Overjustification Effect
• When external rewards undermine the intrinsic
satisfaction of performing a behavior
– Makes people only do something for reward or prize
and not for pure joy
– Usually the reward may lesson and replace the
person’s original, natural motivation so that the
behavior stops if the reward is eliminated
• Pizza for reading
– “what, I don’t get a free pizza for reading 10
books?”
Punishment
• Flip side of reinforcement
• The introduction of a bad
stimulus or the removal of a
reinforcing stimulus after a
response occurs
– Weakens a behavior or makes it
less likely to occur again in the
future
Does punishment work?
Yes, but…
Often tells the learner what behavior should NOT
exhibited and not what behavior should be
And…don’t forget the Premack Principle
be
Difference between Negative
Reinforcement and Punishment
 Punishment


the introduction of a negative consequence
after a behavior weakens the behavior
Time out for hitting other children
 Negative


Reinforcement
the removal of a negative stimulus after a
behavior strengthens the behavior
Picking up a crying baby