Download General Psychology: Learning (II)

Learning
Chapter 5
Part II
William G. Huitt
Last revised: May 2005
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 occurrence.
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 SUBTRACTED 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/
Aversive
Subtract
Negative
Reinforcement
Add
Punishment
Operant Conditioning
• Two stages of negative reinforcement
– Escape learning
• Learning to perform a behavior because it terminates an
aversive event
– Avoidance learning
• Learning to avoid events or conditions associated with
dreaded or aversive outcomes
• Many avoidance behaviors are maladaptive and occur in
response to phobias
Operant Conditioning
• Disadvantages of punishment and response
cost
– Punishment and response cost do not extinguish
an undesirable behavior; rather, they suppress
that behavior when the punishing agent is
present.
– Punishment and response cost indicate that a
behavior is unacceptable but does not help
people develop more appropriate behaviors.
Operant Conditioning
• Disadvantages of punishment and response
cost
– The person who is severely punished often
becomes fearful and feels angry and hostile
toward the punisher. These reactions may be
accompanied by a desire to retaliate or to avoid
or escape from the punisher and the punishing
situation.
– Punishment frequently leads to both negative
affect and aggression. Those who administer
physical punishment may become models of
aggressive behavior.
Operant Conditioning
• Shaping behavior
– An operant conditioning technique that consists of
gradually molding a desired behavior (response) by
reinforcing responses that become progressively
closer to the desired behavior
– B. F. Skinner demonstrated that shaping is
particularly effective in conditioning complex
behaviors
Operant Conditioning
• Shaping behavior
– Successive approximations
• A series of gradual steps, each of which is more like the
final desired response
– The motives of the shaper and the person or animal
whose behavior is being shaped are different
– The shaper seeks to change another’s behavior by
controlling its consequences
– The person or animal’s motive is to gain rewards or
avoid unwanted consequences
Use Conditioning to Modify Your Own Behavior
1. Identify the target behavior.
• observable
• measurable
2. Gather and record baseline data.
• daily record
• note where the behavior takes place
• note cues (or temptations) in the environment
3. Plan your behavior modification program.
• Set goals (small steps, moderate & systematic change)
• Develop steps and actions
Use Conditioning to Modify Your Own Behavior
4.
Choose reinforcers
• Pick appropriate for action
• Be prepared for not receiving
5.
Set the reinforcement conditions and begin recording
and reinforcing your progress.
• Keep in mind Skinner’s concept of shaping – rewarding small
steps toward the desired outcome.
• Be perfectly honest with yourself and claim a reward only when
you meet the goals.
• Chart your progress as you work toward gaining more control
over the target behavior.
Schedules of consequences
Stimuli are presented in the environment according
to a schedule of which there are two basic
categories:
• Continuous
• Partial or 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: Student raises hand to be called on.
Schedules of consequences
Pattern of behavior for variable ratio schedule
Rules In Analyzing Examples
• The following questions can help in determining
whether operant conditioning has occurred.
a. What behavior in the example was increased
or decreased?
b. Was the behavior
• increased (if yes, the process has the be
either positive or negative reinforcement),
OR
• decreased (if the behavior was decreased
the process is either response cost or
punishment).
Rules In Analyzing Examples
• The following questions can help in determining
whether operant conditioning has occurred.
c. What was the consequence / stimulus that
followed the behavior in the example?
d. Was the consequence (stimulus) added or
removed?
• If added, the process was either positive
reinforcement or punishment.
• If it was subtracted, the process was either
negative reinforcement or response cost.
Analyzing An Example
Billy likes to campout in the backyard. He campedout on every Friday during the month of June. The
last time he camped out, some older kids snuck up
to his tent while he was sleeping and threw a bucket
of cold water on him. Billy has not camped-out for
three weeks.
a. What behavior was changed?
Camping out
Analyzing An Example
Billy likes to campout in the backyard. He campedout on every Friday during the month of June. The
last time he camped out, some older kids snuck up
to his tent while he was sleeping and threw a bucket
of cold water on him. Billy has not camped-out for
three weeks.
b. Was the behavior strengthened or
weakened?
Weakened (Behavior decreased)
Eliminate positive and negative reinforcement
Analyzing An Example
Billy likes to campout in the backyard. He campedout on every Friday during the month of June. The
last time he camped out, some older kids snuck up
to his tent while he was sleeping and threw a bucket
of cold water on him. Billy has not camped-out for
three weeks.
c. What was the consequence?
Having water thrown on him.
d. Was the behavior consequence added or
subtracted?
Added
Analyzing An Example
Billy likes to campout in the backyard. He campedout on every Friday during the month of June. The
last time he camped out, some older kids snuck up
to his tent while he was sleeping and threw a bucket
of cold water on him. Billy has not camped-out for
three weeks.
Since a consequence was ADDED and the
behavior was WEAKENED (REDUCED),
the process was PUNISHMENT.
Classical vs Operant Conditioning
• Processes of generalization, discrimination,
extinction, and spontaneous recovery occur in
both classical and operant conditioning
• Both types of conditioning depend on
associative learning
• In classical conditioning, an association is
formed between two stimuli
• In operant conditioning, the association is
established between a response and its
consequences
Classical vs Operant Conditioning
• In classical conditioning, the focus is on what
precedes the response
• In operant conditioning, the focus is on what
follows the response
• In classical conditioning, the subject is passive
and responds to the environment rather than
acting on it
• In operant conditioning, the subject is active
and operates on the environment