Operant Conditioning
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A form of learning in which behavior
becomes more or less probable depending
on its consequences
Associated with B.F. Skinner
Four possible consequences to
behavior
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Something good could start or be presented
Something good could stop or be taken away
Something bad could start or be presented
Something bad could stop or be taken away
In operant conditioning, the word “positive” means that
something starts or is added.
The word “negative” means that something is taken away
or stopped.
Reinforcement
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Increase in probability of a response caused
by stimuli (consequence) that follows it
Goal is to increase the behavior
Reinforcers make behavior occur more
frequently, make it more likely to occur, or
make it occur more strongly.
Punishment
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Decrease in the probability of a response
caused by the stimuli (consequence) that
follow it
Goal is to decrease the behavior—make it
occur more weakly, less often, or less
likely to occur at all.
Two types of reinforcement
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Positive reinforcement: response is
strengthened because it’s followed by
presentation of a desirable stimulus
Negative reinforcement: response is
strengthened because it’s followed by
removal of an aversive stimulus
Two types of punishment
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Positive punishment: aversive event
following a response; decreases the
tendency to make the response
Negative punishment: removal of a
desirable stimulus following a response;
decreases the tendency to make the
response
Reinforcement/Punishment Chart
Reinforcement
(behavior increases)
Punishment (behavior
decreases)
Positive (something
added)
Positive reinforcement
(Something good added
increases behavior)
Positive punishment
(Something unpleasant
added decreases
behavior)
Negative (something
taken away)
Negative reinforcement
(Something bad taken
away increases behavior)
Negative punishment
(Something good taken
away decreases behavior)
Is punishment effective?
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Effective in decreasing responses, but sometimes
it results in suppression of all behavior if
punishment is too severe
To make it more effective:
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Apply swiftly
Be just severe enough to be effective
Be consistent
Explain the punishment
Reinforce alternative behavior
In general…
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Consequences—good or bad—must be
either immediate (in the case of animals) or
clearly explained to the individual in which
it is made clear that the consequence is
linked to the behavior.
Shaping
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A way to teach someone a new behavior that he’d
never perform naturally
Person or animal is reinforced for successive
approximations of a target behavior, and finally,
for the behavior itself
Person or animal receives a small reward for each
small step toward a final goal, rather than just a
reward for the target response
Schedules of reinforcement
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How often are you reinforced for your behavior?
Could be continuous or partial.
Continuous: you get a reinforcement/reward
every time you perform the behavior
Partial: you get a reinforcement after only a
certain amount of time has passed (interval
schedule) or after a certain number of responses
(ratio)
Fixed ratio
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Provides reinforcement after a specific
number of desired responses
High, steady response rate
Brief post-reinforcement pause
Example: Getting paid every time you sell
another 5 magazine subscriptions
Fixed Ratio Graph
Fixed interval
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Provides reinforcement after a set period of time
Produces a drop in responding immediately after
reinforcement (post-reinforcement pause) and a
gradual increase in responding at the time for the
next reinforcement
Scalloping: greatly exaggerated postreinforcement pause
Worst schedule to use in education, but it’s often
used (e.g., test every second Friday)
Fixed Interval Graph
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Notice the scalloping pattern.
Variable ratio schedule
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Provides reinforcement after an
unpredictable number of desired resp onses
High steady rates of responding
Highest burnout rate
Produces behaviors that are highly resistant
to extinction, persist long after the
reinforcement isn’t available any more.
Called the partial reinforcement effect.
Graph of variable ratio schedule
Variable interval schedule
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Provides reinforcement for the first desired
response made after varying periods of
time
Slow, steady rate of responding
Less chance of burnout
Best schedule, especially for education
(e.g., unannounced pop quizzes)
Example: fishing (waiting for fish to bite)
Variable Interval Schedule
Summary of Schedules
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Ratio schedules—faster response rates than
interval schedules because number of
responses, not passage of times, determines
reinforcement
Variable schedules—steadier response
rates than fixed schedules because people
don’t know when their payoff will be.
A comparison of the schedules of reinforcement
Notice that the ratio schedules produce faster, higher response rates than
the interval schedules. Variable schedules produce steadier response rates
fixed schedules. There are no scalloping patterns or postreinforcement
pauses with variable schedules.
Premack Principle
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What’s an effective reinforcer for one
person might not be an effective reinforcer
for another
Example: Giving kids M&Ms to turn
knobs; sometimes turning knobs is more
fun than getting M&Ms.
Observational Learning
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Occurs when a behavior is learned by
observing the consequences that others
receiver for performing it; MODELING.
Also called “Social Learning”
Bandura, Ross, & Ross (1963): Bobo doll
study
Footage of the Bobo doll study
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http://video.google.com/videoplay?docid=2953790276071699877#docid=4586465813762682933
Questions about observational
learning
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Why would a child imitate a behavior if it
isn’t reinforced? Because imitation aids in
survival and adaptation, and it’s favored by
natural selection.
Do other species use observational
learning? Yes, it’s even been demonstrated
in cockroaches.
Processes that must take place for
observational learning to occur
Attention to model’s actions
 Retention of model’s actions
 Reproduction of model’s actions
 Motivation to perform model’s actions
You may acquire a behavior but not perform it
if you see the performance will result in
negative consequences.
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