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Operant Conditioning
Overview
http://www.youtube.com/watch?v=drnnulHw5CM
Edward Thorndike (1874-1949)
• Introduced the “Law of Effect”
• Behaviors with favorable consequences
will occur more frequently.
• Behaviors with unfavorable
consequences will occur less frequently.
• Developed into Operant Conditioning
• Created puzzle boxes for research on cats
Thorndike’s Puzzle Box
Operant Conditioning
• A type of learning in which the frequency of a
behavior depends on the consequence that
follows that behavior
• The frequency will
if the consequence is
reinforcing to the subject.
• The frequency will
if the consequence is
not reinforcing to the subject.
B.F. Skinner (1904-1990)
• Developed the fundamental principles
and techniques of operant conditioning.
• Devised ways to apply these principles in
the real world.
• Designed the Skinner
Box.
Reinforcement v. Punishment
• Reinforcement: Anything that
increases the likelihood of
behavior to be repeated
• Punishment: Anything that
decreases the likelihood of the
behavior to be repeated
Positive Reinforcement
• Anything that increases the likelihood of
a behavior by following it with a
desirable event or state
• The subject receives something they want
• Will strengthen the behavior
Positive Reinforcement
Negative Reinforcement
• Anything that increases the likelihood of a
behavior by following it with the removal of
an undesirable event or state
• Something the subject doesn’t like is
removed
• Will strengthen the behavior (Definition of
Reinforcement)
Negative Reinforcement
Positive Punishment
• Anything that decreases the likelihood of
a behavior by following it with an
undesirable event or state
• Will weaken behavior
Negative Punishment
• Anything that decreases the likelihood of
a behavior by following it with removal of
an desirable event or state
• Will weaken behavior
Go to bed with
no dinner!
Two types of Punishment:
POSITIVE
(ADDED)
REINFORCEMENT
(STRENGTHENS)
PUNISHMENT
(WEAKENS)
NEGATIVE
(SUBTRACTED)
• Clean the house and earn
$5
• a coach pats you on the
back after a good play
• a paycheck for working
• $10 for getting an “A” on
your report card
• Senior privilege for
maintaining good grades
• You buy your child ice
cream so they stop nagging
• You leave early for school
to avoid traffic
• You take Tylenol to remove
back pain
• You get your mouth
washed out with soap when
you curse
• Touch and hot stove and
get burned
• Getting a ticket for
speeding
• You lose your driving
privileges for breaking
curfew
• Time out, or the loss of
freedom to combat bad
behavior
• You pay money for a
speeding ticket
Schedules of Reinforcement
• By Response:
– Fixed Ratio: Rewarded after a certain
number of responses (same every time)
– Variable Ratio: Rewarded after a random
number of responses (changes between
rewards)
• By time:
– Fixed Interval: Rewarded after a certain
amount of time (same every time)
– Variable Interval: Rewarded after a random
amount of time (changes between rewards)
Immediate/Delayed Reinforcement
• Immediate reinforcement is more
effective than delayed reinforcement
• Ability to delay gratification predicts
higher achievement
Ways of Reinforcement
Schedules of
Reinforcement:
Continuous
Reinforcement
Continuous reinforcement
• A schedule of reinforcement in which a
reward follows every correct response
• Most useful way to establish a behavior
• The behavior will extinguish quickly
once the reinforcement stops.
Think of training your dog… like this woman did.
Schedules of
Reinforcement:
Partial Reinforcement
Partial Reinforcement
• A schedule of reinforcement in which a
reward follows only some correct
responses
• Includes the following types:
– Fixed-interval and variable interval
– Fixed-ratio and variable-ratio
Fixed-Interval
Schedule
• A partial reinforcement schedule that
rewards only the first correct response
after some defined period of time
• i.e. weekly quiz in a class
Fixed interval schedule is when the reinforcement
is received after a fixed amount of time has passed.
Ex. You get allowance every other Friday.
Variable-Interval
Schedule
• A partial reinforcement
that rewards the first
correct response after an
unpredictable amount
of time
• i.e. “pop” quiz in a class
Variable interval schedule is when the
reinforcement occurs after varying amounts of time.
Ex. Fishing and catching a fish after varying amounts
of time
Fixed-Ratio Schedule
• A partial reinforcement schedule that
rewards a response only after some
defined number of correct responses
• The faster the subject responds, the
more reinforcements they will receive.
Fixed ratio schedule a specific number of correct
responses is required before reinforcement can be
obtained. Ex. Buy 10 haircuts get 1 free.
Variable-Ratio Schedule
• A partial reinforcement schedule that
rewards an unpredictable number of
correct responses
• This schedule is very resistant
to extinction.
• Sometimes called the “gambler’s
schedule”; similar to a slot machine
Variable ratios schedule is when an unpredictable
number of responses are required before
reinforcement can be obtained. Ex. slot machines.
Schedules of Reinforcement
Kindergarten Study
•
Children who showed high interest in
drawing were selected, then split into 3
groups
1. 1 group given good player badge and told
they would get it if they did a good job
drawing
2. 1 group given badge but weren’t expecting
the reward
3. 1 group given no reward after drawing
•
Which group drew the most the next
day?
– Answer: Group 1 drew the least, 2,3 more
• Overjustification Effect: rewarding an
already enjoyable behavior may replace
natural enjoyment with expectation of reward
Should we pay students when
they get better grades?
Bandura’s Experiment
•
In Albert Bandura’s Bobo Doll experiment
children observed others modeling violent
behavior towards a blow-up doll.
1. Another adult rewards the adult model with praise
and candy. One group of children saw this ending.
2. Another adult calls the model a “bad person” and
spanks the model. A second group of children saw
this ending.
3. The model receives neither a reward nor a
punishment. A final group saw this neutral ending.
•
What would you expect the results of this
experiment to be?
Results of Bandura Experiment
• Children who saw the
model receiving
positive reinforcement
were the most violent
• Those who saw the
model being punished
were the least violent
Modeling – learning by imitating/copying
Bobo-Doll Experiment
Bandura demonstrated that
children learn aggressive
behaviors by watching an
adult’s aggressive
behaviors.
Albert Bandura found that we learn by watching others if the following
four conditions are met:
• Attention – We must be aware of behaviors of those around us
•
Retention – We must remember the behavior we have witnessed
• Ability to Reproduce Behavior – We must possess the skills to do
the tricks
•
Motivation – We are more likely to feel motivated to learn if the
model we’ve observed has been rewarded and we like the model
• Behaviors produced can either be
prosocial or antisocial behaviors
– Prosocial: Beneficial (helping people,
obeying rules, etc.)
– Antisocial: Damaging (vandalism, violence,
etc)
Role Models
• Can people choose to be role models?
– Whether we want it or not, people watch us and learn
from us.