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Operant Conditioning
Operant Conditioning
The major theorists for the development of
operant conditioning are:
• Edward Thorndike
• John Watson
• B.F. Skinner
Operant Conditioning
• Operant conditioning investigates the influence of
consequences on subsequent behavior.
• Operant conditioning investigates the learning of
voluntary responses.
• It was the dominant school in American
psychology from the 1930s through the 1950s.
Operant Conditioning
• Where classical conditioning illustrates S-->R
learning, operant conditioning is often viewed as R->S learning
• It is the consequence that follows the response
that influences whether the response is likely or
unlikely to occur again.
Operant Conditioning
• The three-term model of operant conditioning (S-> R -->S) incorporates the concept that responses
cannot occur without an environmental event (e.g.,
an antecedent stimulus) preceding it.
• While the antecedent stimulus in operant
conditioning does not ELICIT or CAUSE the
response (as it does in classical conditioning), it
can influence its occurance.
Operant Conditioning
• When the antecedent does influence the
likelihood of a response occurring, it is
technically called a discriminative stimulus.
• It is the stimulus that follows a voluntary
response (i.e., the response's consequence) that
changes the probability of whether the response is
likely or unlikely to occur again.
Operant Conditioning
• There are two types of consequences:
– positive (sometimes called pleasant)
– negative (sometimes called aversive)
Operant Conditioning
• Two actions can be taken with these stimuli:
– they can be ADDED to the learner’s environment.
– they can be SUBRACTED from the learner’s
environment.
• If adding or subtracting the stimulus results in a
change in the probability that the response will
occur again, the stimulus is considered a
CONSEQUENCE.
• Otherwise the stimulus is considered a
NEUTRAL stimulus.
Operant Conditioning
• There are 4 major techniques or methods used in
operant conditioning.
• They result from combining:
– the two major purposes of operant conditioning
(increasing or decreasing the probability that a
specific behavior will occur in the future),
– the types of stimuli used (positive/pleasant
or negative/aversive), and
– the action taken (adding or removing the
stimulus).
Operant Conditioning
Outcomes of Conditioning
Stimulus
Increase Behavior
Decrease
Behavior
Positive/
pleasant
Add
Positive
Reinforcement
Subtract
Response Cost
Negative/A
versive
Subtract
Negative
Reinforcement
Add
Punishment
Schedules of consequences
Stimuli are presented in the environment
according to a schedule of which there are two
basic categories:
• Continuous
• Intermittent
Schedules of consequences
Continuous reinforcement simply means that
the behavior is followed by a consequence each
time it occurs.
• Excellent for getting a new behavior
started.
• Behavior stops quickly when reinforcement
stops.
• Is the schedule of choice for punishment
and response cost.
Schedules of consequences
Intermittent schedules are based either on the
• passage of time
OR
• number of correct responses
Schedules of consequences
The consequence can be delivered based on
• a fixed amount of time or number of
correct responses
OR
• a slightly different amount of time or number
of responses that vary around a particular
number
Schedules of consequences
This results in an four classes of intermittent
schedules.
Fixed Interval
• The first correct response after a set amount of time
has passed is reinforced (i.e., a consequence is
delivered).
• The time period required is always the same.
• Example: Spelling test every Friday.
Schedules of consequences
Pattern of behavior for fixed interval schedule
Schedules of consequences
Variable Interval
• The first correct response after a set amount of time
has passed is reinforced (i.e., a consequence is
delivered).
• After the reinforcement, a new time period (shorter
or longer) is set with the average equaling a specific
number over a sum total of trials.
• Example: Pop quiz
Schedules of consequences
Pattern of behavior for variable interval schedule
Schedules of consequences
Fixed Ratio
• A reinforcer is given after a specified number of
correct responses. This schedule is best for learning a
new behavior.
• The number of correct responses required for
reinforcement remains the same.
• Example: Ten math problems for homework
Schedules of consequences
Pattern of behavior for fixed ratio schedule
Schedules of consequences
Variable Ratio
•A reinforcer is given after a set number of correct
responses.
• After reinforcement the number of correct responses
necessary for reinforcement changes. This schedule is
best for maintaining behavior.
• Example: A student raises his hand to be called
on.
Schedules of consequences
Pattern of behavior for variable ratio schedule
Premack Principle
• The Premack Principle, often called "grandma's
rule," states that a high-frequency activity can be
used to reinforce low-frequency behavior.
• Access to the preferred activity is contingent on
completing the low-frequency, non-preferred
behavior.