OPERANT
CONDITIONING
DEF: A FORM OF LEARNING IN WHICH RESPONSES
COME TO BE CONTROLLED BY THEIR CONSEQUENCES
THORNDIKE’S LAW OF EFFECT
• Edward L. Thorndike
• Studied instrumental
learning
• This is the
foundation of
operant
conditioning
• Cat studies
LAW OF EFFECT
• DEF: if a response in
the presence of a
stimulus leads to a
satisfying effects,
the association
between the
stimulus and the
response is
strengthened
• The cornerstone of
B.F. Skinner’s theory
SKINNER’S DEMONSTRATION
• Skinner showed that
organisms tend to
repeat those responses
that are followed by
favorable
consequences
• Reinforcement: occurs
when an event
following a response
increases an
organism’s tendency to
make that response
TERMINOLOGY
• Operant chamber: “Skinner Box”, a small enclosure
in which an animal can make a specific response
that is recorded while the consequences of the
response are systematically controlled
• Used to control Reinforcement contingencies: rules
that determine whether response lead to the
presentation of reinforcers
OPERANT CONDITIONING
• Key dependent
variable is subject’s
response rate over
time
• Cumulative
recorder: creates a
graphic record of
responding and
reinforcement in a
Skinner box as a
function of time
BASIC PROCESSES OF OPERANT
CONDITIONING
• Shaping: the
reinforcement of
closer and closer
approximations of a
desired response
• Important in
acquisition
• Necessary when an
organism does not
emit the desired
response
BASIC PROCESSES OF OPERANT
CONDITIONING
• Extinction: weakening
and disappearance of
a response tendency
b/c the response is no
longer followed by a
reinforcer
• Resistance to
extinction: when an
organism continues to
make a response after
delivery of the
reinforcer for it has
been terminated
DISCRIMINATIVE STIMULI
• DEF: cues that
influence operant
behavior by
indicating the
probable
consequences of a
response
• Regulate operant
behavior
STIMULUS
GENERALIZATION/DISCRIMINATION
• Generalization:
Responding to a
new stimulus as if it
were the original
• Stimulus
discrimination:
decrease in
response to a new
stimulus that
resembles the
original
REINFORCEMENT
• Strengthening of a
response tendency
• Defined after the
fact, in terms of
effect on behavior
• Reinforcement is
subjective
DELAYED REINFORCEMENT
• Favorable
outcomes are more
likely to strengthen
a response if the
outcome follows
immediately
CONDITIONED REINFORCEMENT
• Primary reinforcers:
events that are
inherently reinforcing
b/c they satisfy
biological needs
• Secondary
(conditioned)
reinforcers: events
that acquire
reinforcing qualities
by being associated
w/primary reinforcers
INTERMITTENT REINFORCEMENT:
EFFECTS OF BASIC SCHEDULES
• Schedule of
reinforcement:
determines which
occurrences of a
specific response
result in the
presentation of a
reinforcer
INTERMITTENT REINFORCEMENT
• Continuous reinforcement: occurs when every
instance of a designated response is reinforced
• Intermittent, partial, reinforcement: occurs when a
designated response is reinforced only some of the
time
• Intermittent makes a response more resistant to
extinction
• There are 4 types of intermittent reinforcement…
FIXED-RATIO (FR) SCHEDULE
• Ratio schedules
require the organism
to make a response a
certain amount of
times to gain a
reinforcer
• FR Schedule: the
reinforcer is given
after a fixed number
of nonreinforced
responses
VARIABLE-RATIO (VR) SCHEDULE
• The reinforcer is
given after a
variable number of
nonreinforced
responses
FIXED-INTERVAL (FI) SCHEDULE
• Interval schedules
require a time
period to pass btwn
presentation of
reinforcers
• FI Schedule: the
reinforcer is given
for the 1st response
that occurs after a
fixed time interval
has elapsed
VARIABLE-INTERVAL (VI) SCHEDULE
• The reinforcer is
given for the 1st
response after a
variable time
interval has elapsed
• Interval length
depends on a
predetermined avg.
RATIO VS. INTERVAL
• Ratio schedules produce more rapid responding
• Variable schedules tend to generate steadier
response rates and greater resistance to extinction
CONCURRENT SCHEDULES OF
REINFORCEMENT
• Concurrent
schedules of
reinforcement:
consist of 2 or more
reinforcement
schedules that
operate
simultaneously and
independently,
each for a different
response
MATCHING LAW
• States that under concurrent schedules of
reinforcement, organisms’ relative rate of
responding to each alternative tends to match
each alternative’s relative rate of reinforcement
• Quality of reinforcement earned also effects
response rate
• Assumes organisms are working to maximize their
overall reinforcement
MATCHING AND FORAGING
• Optimal foraging
theory: food
seeking behaviors
of many animals
maximize the
nutrition gained in
relation to the
energy expended
to locate, secure,
and consume
various foods
POSITIVE REINFORCEMENT
• Occurs when a
response is
strengthened b/c it
is followed by the
presentation of a
rewarding stimulus
NEGATIVE REINFORCEMENT
• Occurs when a
response is
strengthened b/c it is
followed by the
removal of an
aversive stimulus
• Don’t be confused
by word negative
• Many everyday
behaviors effected
by negative
reinforcement
ESCAPE LEARNING
• Def: an organism
acquires a response
that decreases or
ends some aversive
stimulation
• Shuttle box
AVOIDANCE LEARNING
• DEF: an organism
acquires a response
that prevents some
aversive stimulation
from occurring
• Avoidance learning
responses are very
resistant to
extinction
TWO-PROCESS THEORY OF AVOIDANCE
• Avoidance begins b/c classical conditioning
creates a conditioned fear
• Avoidance is maintained by operant conditioning
• Avoidance response is strengthened through
negative reinforcement
PUNISHMENT: CONSEQUENCES THAT
WEAKEN RESPONSES
• Punishment occurs
when an event
following a
response weakens
the tendency to
make that response
• NOT NEGATIVE
REINFORCEMENT!!!
PUNISHMENT
• Can have side effects:
• General suppression of
behavioral activity
• Trigger strong
emotional responses
• Physical punishment
often leads to
aggressive behavior
• More effective to
reinforce desirable
behavior than punish
undesirable behavior