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DEPARTMENT OF BEHAVIOURAL
SCIENCES
B.SC (HUMAN BIOLOGY) TEACHING
PROGRAM
FOUNDATION OF BEHAVIOURAL SCIENCES
COURSE CODE: SMS 154
LEARNING THEORIES
• Learning is a field of study in which the
behaviorists have traditionally dominated.
• The school of behaviorism rose to a large
extent as a protest group against what they
perceived as excessive emphasis on the
unconscious by the Structuralists and the
functionalists.
LEARNING THEORIES – CONT’D
• The behaviorists insisted that psychology study only
observable, measurable behaviour, without
reference to unobservable mental processes.
• Even within their ranks, there are divisions; we have
the methodological behaviorists who maintain that
psychology should study only the events that they
can measure and observe – in other words stimulus
and response.
• Mental processes to them may well exist, but may
not be included in their science; or if they include
them, they cautiously inferred from behaviour.
LEARNING THEORIES – CONT’D
• The radical behaviorists on the contrary do
not want to have anything to do with mental
processes. B. F Skinner (1990) argued, when
you say, “ I intend to…” you really mean “ I am
about to…”
• That was a good way of saying that any
statements alluding to intensions should be
converted into a description of behaviour.
DEFINING LEARNING
LEARNING ? NON PSYCHOLOGICAL
• Learning is acquiring new knowledge, behaviors,
skills, values, preferences or understanding,
– may involve synthesizing different types of
information.
• The ability to learn is possessed by humans,
animals and some machines (artificial
intelligence).
LEARNING?
• Human learning may occur as part of
– education,
– personal development, or
– training.
– It may be goal-oriented and may be aided by
motivation.
• The study of how learning occurs is part of
neuropsychology, educational psychology,
learning theory, and pedagogy.
CONSCIOUS/ UNCONSCIOUS?
• Learning may occur consciously or without
conscious awareness.
HOW EARLY?
• There is evidence for human behavioral
learning prenatally, in which habituation has
been observed as early as 32 weeks into
gestation,
• That’s an indication that the central nervous
system is sufficiently developed and primed
for learning and memory to occur very early
on in development.
TYPES OF LEARNING
SIMPLE AND COMPLEX
TYPES OF LEARNING
• SIMPLE NON – ASSOCIATIVE
– Habituation
– Sensitization
• ASSOCIATIVE
– Operant
– Classical
• IMPRINTING
• OBSERVATIONAL / IMITATIONAL/ VICARIOUS/ L/ MODELING
COMPLEX TYPES OF LEARNING
• More complex forms of learning include higher- level
learning involving
–
–
–
–
–
memory
Comprehension & language,
concepts, and
motor skills.
and other information - rich mental processes.
• In this lecture we shall be concerned with a more basic
form of learning (non associative & associative).
LEARNING THEORIES – CONT’D
• In everyday usage/ everyday sense, learning often
refers to formal methods of acquiring new
knowledge or skills, such as learning in the classroom
or learning to play an instrument.
• It is common to think of learning as something
that takes place in school, but much of human
learning occurs outside the classroom, and
people continue to learn throughout their
lives.
LEARNING THEORIES – CONT’D
• Even before they enter school, young children learn
to walk, to talk, and to use their hands to manipulate
toys, food, and other objects.
• They use all of their senses to learn about the sights,
sounds, tastes, and smells in their environments.
• They learn how to interact with their parents,
siblings, friends, and other people important to their
world. When they enter school, children learn basic
academic subjects such as reading, writing, and
mathematics.
LEARNING THEORIES – CONT’D
• They also continue to learn a great deal outside the
classroom. They learn which behaviors are likely to
be rewarded and which are likely to be punished.
• They learn social skills for interacting with other
children.
• After they finish school, people must learn to adapt
to the many major changes that affect their lives,
such as getting married, raising children, and finding
and keeping a job..
LEARNING THEORIES – CONT’D
• Because learning continues throughout our lives and
affects almost everything we do, the study of
learning is important in many different fields.
• Teachers need to understand the best ways to
educate children. Psychologists, Optometrists, social
workers, criminologists, Doctors and other humanservice workers need to understand how certain
experiences change people’s behaviors.
• Employers, politicians, and advertisers make use of
the principles of learning to influence the behavior of
workers, voters, and consumers.
LEARNING THEORIES – CONT’D
• what is learning? – Psychological?
DEFINING LEARNING
• Definition of learning – very difficult.
– Subjects with language capabilities could inform the researcher by
way of verbal communication
– What happens when they cannot communicate?
• E.g. in animals, newborns, children (trustworthy) etc.
• Only way is to deduce from changes in performance /
behaviour.
– This is overt, objective
– Also unseen/ covert behavior.
• FIRST WORD – changes in performance or “changes in
behaviour”.
• Most importantly; changes in potential behaviour.
DEFINING LEARNING
• So Psychologists may create various situations
conducive to learning and measure a subject’s
performance in each.
• In each of these the situation should be carefully
controlled. Why?
– Several factors temporarily affect performance.
Examples;
• Fatigue*
• Emotions and motivation
• Health and
– These effects are mostly temporal but in learning we
need a more permanent change (s)
DEFINING LEARNING
• Some permanent changes can occur as a result of
MATURATION. E.g. walking, lifting certain weight, is
it learning?
– This does not qualify because it is not a result of prior
experience (Capable because of growth).
– When you were young, you could not do certain things
but when you matured physically, they became easier to
do
– So some form of EXPERIENCE is necessary
DEFINING LEARNING
• To distinguish learning from physically
based factors, such as maturation or
illness,
• learning can be designated as a change in
performance/ performance potential
that result from experience.
IMPORTANT WORDS
• EXPERIENCE
• Relatively permanent
• Changes in behaviour/ potential behaviour
– E.g Curfew in Tamale
– Experiences here @ SMS – acquiring changes in your
behaviour/ acquiring potential behavior to be able to
treat patients in near future.
• Any single, all embracing definition?
DEFINITION OF LEARNING
• Various definitions. For e g. Coon (1992)*** defines
learning as “any relatively permanent change in behavior
that can be attributed to experience” p. 189.
• Notice that this definition excludes temporary changes
caused by motivation, fatigue, maturation,
disease/injury, drugs and so forth”
• Morris and Maesto (1999) define it as “a process by
which experience or practice results in a relatively
permanent change in behavior or potential behaviour, p
166.
LEARNING DEFINITION – CONT’D
• NB: potential behaviour from Morris & Maesto
• Hockenbury and Hockenbury (2001) see learning as a
process that produces a relatively enduring change in
behaviour or knowledge as a result of an individual’s
experience, p 163.
• Kassin (2001; 174) referred to learning as a relatively
permanent change in knowledge or behaviour that
comes about as a result of experience.
KEYWORDS
•
•
•
Relatively Permanent Change
Experience and
Behaviour/Potential behaviour
–
It implies that all sorts of events/experience could
result in changes in behavior but not all would be
regarded as relatively permanent.
–
Some of these include fatigue, maturation (an
automatic biological unfolding of development in an
organism as a function of passage of time), drugs or
injury
HOW OF LEARNING
• The definitions say nothing about HOW
learning actually takes place.
• There are different kinds of learning
• How we learn, to a large extent depend in
large part on what we are learning.
LEARNING THEORIES – CONT’D
• Learning is closely related to memory, which is the storage
of information in the brain.
– Psychologists who study memory are interested in how
the brain stores knowledge, where this storage takes
place, and how the brain later retrieves knowledge
when we need it.
• In contrast, psychologists who study learning are more
interested in behavior and how behavior changes as a
result of a person’s experiences.
LEARNING THEORIES – CONT’D
• There are many forms of learning, ranging from simple to
complex. (More complex forms of learning include learning languages, concepts,
and motor skills).
• Simple forms of learning involve a single stimulus (e.g..
habituation).
– A stimulus is anything perceptible to the senses, such as a sight, sound, smell,
touch, or taste.
SIMPLE LEARNING
NON - ASSOCIATIVE
I.
II.
HABITUATION &
SENSITIZATION
TYPES OF LEARNING
• One of the simplest kind of the learning is acquiring the
knowledge that things in the environment exist and differ
from one another.
• We accomplish this by examining new stimuli with our
senses (Curiosity & exploration).
• Unfamiliar, intense, or unexpected stimulus tends to
produce an ORIENTING REFLEX
– A response that involves a whole chain of activities
•
•
•
•
Looking
Listening
Touching &
Sniffing
– Designed to find out what the new stimulus is about.
– What happens when we repeatedly encounter the same stimuli?
ORIENTING REFLEX
•The orienting response disappears
The unfamiliar becomes a commonplace
•Psychologists say HABITUATION has occurred. (Habituated
to that stimulus)
HABITUATION
• In psychology, habituation is an example of non-associative
learning in which there is a progressive diminution of
behavioral response probability with repetitive stimulus.
• THUS, there’s a tendency to become familiar with a
stimulus after repeated exposure to it.
• An animal first responds to a stimulus, but if it is neither rewarding
nor harmful the animal reduces subsequent responses.
• A common example of habituation occurs in the orienting
response, in which a person’s attention is captured by a loud or
sudden stimulus.
HABITUATION
• For example, a person who moves to a house on a
busy street may initially be distracted (an orienting
response) every time a loud vehicle drives by.
• After living in the house for some time, however, the
person will no longer be distracted by the street noise
–
• the person becomes habituated to it and the
orienting response disappears
LEARNING THEORIES – CONT’D
• Despite its simplicity, habituation is a very useful
type of learning.
– Because our environments are full of sights and sounds,
we would waste a tremendous amount of time and
energy if we paid attention to every stimulus each time
we encountered it.
– Habituation allows us to ignore repetitive, unimportant
stimuli. Habituation occurs in nearly all organisms, from
human beings to animals with very simple nervous
systems.
• Even some one-celled organisms will habituate to a light,
sound, or chemical stimulus that is presented repeatedly.
HABITUATION - EXPERIMENT
• Friedman (1972) demonstrated this by an experiment?
– He showed newborn babies a picture of checkerboard patterns.
– Each time, the baby looks at it for nearly the full minute it is
visible.
– This is carried out for six presentations, what happens after this?
– Then, on the seventh and eight presentations, the baby looks for
only half a minute before turning away.
• What happens that the infant now looks for it for half
instead of a full minute after the sixth presentation???
HABITUATION - EXPERIMENT
– Has the child grown sleepy/ having trouble paying attention?
– Has the infant learned the check - board pattern and become
bored with it?
• That is an example of orienting reflex followed by
habituation in the infant's response to the checkerboard
pattern.
– At 1st the baby was very interested in the picture, but after a
while she began to look away.
• We behave the same way many times each day,
– e.g peculiar rattling noise in your car?
• Likely to pay attention. As time goes by, you don’t notice the noise –
not because it has stopped.
• Why – habituation. What’s the importance??
HABITUATION
• When habituation occurs to a stimulus – we must have
learned something about it.
– In the case of the car noise, we might have learned that this
particular sound exists but doesn’t seem to indicate/ constitute
any serous problem.
• Simple organisms may become habituated. Humans are
no exceptions
– You buy a newly released CD
• After a while u don’t notice it , why?
SENSITIZATION
• Sensitization, another simple form of learning, is
the increase that occurs in an organism’s
responsiveness to stimuli following an especially
intense or irritating stimulus.
– For example, a sea snail that receives a strong electric
shock will afterward withdraw its gill more strongly than
usual in response to a simple touch.
– If your electric iron gives you a shock what happens to
your response/ sensitivity to electric irons?
– Depending on the intensity and duration of the original
stimulus, the period of increased responsiveness can last
from several seconds to several days.
ASSOCIATIVE LEARNING
LEARNING THEORIES
ASSOCITIVE L. (CONDITIONING)
&
SOCIAL LEARNING
Consider the following – how do you explain them?
•
•
•
Situation I
Susie enjoys opening the door
whenever the doorbell goes
.One evening; she answered
the doorbell and at the door
was Julie who had dressed up
in a costume like a monster.
Susie got so terrified that she
nearly passed out when she
started screaming and run
back to lock herself up in her
room upstairs. Later she got
terrified whenever the
doorbell rung.
• Scenario II
– Kofi is a cancer patient
receiving treatment at
the KATH Cancer center.
– Before each Chemotherapy session, he is
given a bowl of ice
cream. The
chemotherapy makes
Kofi Nauseated. Now just
seeing the bowl of ice
makes him feel
nauseated…ANSWER?
Consider the following – how do you
explain them?
• Question!!
• Scenario IV
• Why do most advertisers use
• Subsequently Esther
well known peoples such as
kicked the machine
footballers, actors, singers
anytime it delayed in
etc.
dispensing the drink?
– Abedi Pele loves….
Since Gabriel admired
– Michael Powell …Guinness
Esther so much, he
the power.
adopted her behaviour to
– Bob Santo???
obtain drinks from
• Esther & Gabriel scenario
delaying vending
• In her anger, Esther kicked
machines.
the machine while Gabriel
was still observing.
– Explanation??
ANSWER???
LEARNING THEORIES
OVERVIEW – LEARNING THEORIES
• INTRODUCTION & DEFINITIONS
• SIMPLE FORMS OF LEARNING
– Habituation
– Sensitization
• CLASSICAL CONDITIONING…
Ivan Pavlov
– Pavlov’s experiment
– Principles of classical conditioning
•
•
•
•
Acquisition,
Extinction,
Generalization &
Discrimination
– Applications of classical/ Pavlovian principles
PIX. OF IVAN PATROVICH PAVLOV
OVERVIEW – LEARNING THEORIES
• OPERANT CONDITIONING...E. L. Thorndike/ Skinner
– Thorndike's experiment & Laws of effect
– B.F Skinner’s research
– Principles of Operant Conditioning
•
•
•
•
•
•
Reinforcement
Schedules of Reinforcement
Punishment
Shaping
Extinction
Generalization & Discrimination
– Applications of operant/ Skinnerian conditioning
PIX. OF SKINNER / THORNDIKE
OVERVIEW – LEARNING THEORIES
• OBSERVATIONAL/ VICARIOUS LEARNING/
MODELING… Albert Bandura
– Bandura’s Experiment
– Bandura’s theory of Imitation\
– Factor’s affecting imitation
– Does TV have influence on behaviour acquisition
PIX. OF ALBERT BANDURA
LEARNING THEORIES
CLASSICAL CONDITIONING
DEFINING – key words
• CLASSICAL
– name Ivan Pavlov gave to the type of learning
he heuristically discovered
• CONDITIONING
– Refers to the fact that the learner is
“conditioned”; meaning the learner forms an
association, usually between a stimulus and a
response or between two stimuli.
LEARNING THEORIES – CONT’D
• Classical conditioning is a type of learning in
which an animal’s natural response to one object
or sensory stimulus transfers to another stimulus
(formerly neutral).
– This illustration shows how a dog can learn to
salivate to the sound of a tuning fork,
• This was an experiment first carried out in the early
1900s by Russian physiologist Ivan Pavlov.
– For conditioning to occur, the pairing of the food
with the tuning fork (step 3 in the illustration) must
be repeated many times, so that the dog eventually
learns to associate the two events.
L. THEORIES – Pavlov’s experiment
• .
CLASSICAL LEARNING
• PAVLOV'S VIDEOS\Pavlov's Dogs Get
Conditioned3.flv
Is this cl.conditioning?
• PAVLOV'S VIDEOS\Psych 120 Classical
Conditioning.flv
CLASSICAL
• Ivan Petrovich Pavlov
• Russian physiologist Ivan Pavlov discovered a
major type of learning, classical conditioning;
• Heuristic discovery while conducting
experiments on digestion in the early 1900s.
He devoted the rest of his life to discovering
the underlying principles of classical
conditioning
L. THEORIES – Pavlov’s experiment
L. THEORIES – Pavlov’s experiment
• Pavlov was studying how saliva aids the digestive
process.
– He would give a dog some food and measure the
amount of saliva the dog produced while it ate
the meal.
• After the dog had gone through this procedure a
few times, however, it would begin to salivate
before receiving any food.
– Pavlov reasoned that some new stimulus, such as the
experimenter in his white coat, had become
associated with the food and produced the response
of salivation in the dog.
– Pavlov spent the rest of his life studying this basic type
of associative learning, which is now called classical
conditioning or Pavlovian conditioning.
L. THEORIES – Pavlov’s experiment
•
•
Consider the following – how do you
explain them?
Situation I
Susie enjoys opening the
door whenever the doorbell
goes .One evening; she
answered the doorbell and at
the door was Julie who had
dressed up in a costume like
a monster. Susie got so
terrified that she nearly
passed out when she
screaming and running back
to lock herself up in her room
upstairs. Later she got
terrified whenever the
doorbell rung.
• Scenario II
– Kofi is a cancer patient
receiving treatment at the
KATH Cancer center. Before
each Chemotherapy session,
he is given a bowl of ice
cream. The chemotherapy
makes Kofi Nauseated. Now
just seeing the bowl of ice
makes him feel nauseated.
– ANSWER?
SOLUTION USING CLASSICAL LEARNING THEORY
• PARADIGM II
PARADIGM I
• Before conditioning
– Doorbell  No fear in Susie
• NS
– Monster costume fear
• UCS
UCR
• During Conditioning (Pairing)
– Doorbell + Julie’s Monster
costume (UCS)  Fear in Susie
(UCR)
• After Conditioning (Pairing)
– Doorbell alone fear in Susie
• CS
CR
• Before conditioning
– Bowl of ice  No Nausea
• NS
– Chemotherapy Nausea
• UCS
UCR
During Conditioning (Pairing)
– Bowl of ice + Chemotherapy (UCS)
 Makes Kofi nauseated (UCR)
After Conditioning (Pairing)
– Bowl of ice alone (CS)  Makes
Kofi feel nauseated (CR)
Principles of Classical Conditioning
• Following his initial discovery, Pavlov spent more
than three decades studying the processes
underlying classical conditioning.
• He and his associates identified four main
processes:
– acquisition,
– extinction,
– generalization, and
– discrimination.
– CONSTIGUITY (READ PLEASE)
AQCUISITION – CONT’D
• The acquisition phase is the initial learning of the
conditioned response - for example, the dog
learning to salivate at the sound of the bell.
• Several factors influence the acquisition of CRs.
Among them are;
– The sequence of CS – UCS presentation,
– The intensity of the UCS and
– The number of times the CS and UCS are paired
AQCUISITION – CONT’D
AQCUISITION – CONT’D
• SEQUENCE OF CS – UCS PRESENTATION
– Influence the strength of the conditioning.
– Up to this point we have simply indicated that that
the CS should precede the US. (Imprecise).
– Rather several sequences for CS – UCS presentation
are possible.
• Trace conditioning
• Delayed conditioning
• Simultaneous conditioning
• Backward conditioning
AQCUISITION – CONT’D
• TRACE CONDITIONING
• Cs comes on and goes be4
the UCS is presented
• Here the UCS is associated
with a memory trace of the
CS, not with the CS itself.
• This produces weaker
conditioning, but not as weak
as simultaneous or backward
conditioning.
AQCUISITION – CONT’D
• DELAYED CONDITIONING
• Comes and stays on, and then the
UCS is presented so that they occur
together for some time
• The presentation of UCS is delayed
for a specific interval after the CS
has been presented
• Researchers found that delayed
conditioning for a short interval
produces a strong conditioning,
whereas longer delays between the
CS & UCS produce weak
conditioning.
• Example, they found 450miliseconds
is the optimal interval for
conditioning the eyelid closure
reflex. (One millisecond = 1/1000 of a
second)
AQCUISITION – CONT’D
• SIMULTANEOUS
CONDITIONING
• CS comes on exactly the
same time as the US.
• Example a sound of a
metronome and the food
powder would be
presented to the dog
simultaneously
• This type results in a weak
conditioning.
AQCUISITION – CONT’D
• BACKWARD
CONDITIONING
• CS comes on after the UCS.
• Example the dog is given food
powder and thereafter hear
the sound of the metronome
• Results in a very weak, if any
conditioning at all.
AQCUISITION – CONT’D
• Conditioning occurs most quickly when the
conditioned stimulus (the bell) precedes the
unconditioned stimulus (the food) by about half a
second.
• Conditioning takes longer and the response is
weaker when there is a long delay between the
presentation of the CS and the UCS
• If the conditioned stimulus follows the
unconditioned stimulus—for example, if the dog
receives the food before the bell is rung —
conditioning seldom occurs.
AQCUISITION – CONT’D
• STRENGTH OF CONDT
• The stronger the UCS , the
stronger the conditioning
– (Holloway & Domjan, 1993)
• When Pavlov gave his dogs a
small amount of meat
powder, they did not salivate
as much as he gave them a
large amount of meat
powder.
– Stronger USCs elicit stronger URs;
– Weaker UCSs produce weaker
URs.
• NUMBER OF (CS- UCS)
PAIRINGS
• The more the CS and the
UCS are paired together, the
stronger the CR becomes.
– If you have eaten at an
exceptionally fine restaurant
several times, your CRs to the
sight of the restaurant and its
menu will be stronger than
would be if you had eaten
there only once. Always
True?? ***
EXTINTION & SPONTANEOUS RECOVERY
• Once learned, a conditioned response is not necessarily
permanent.
• The term extinction is used to describe the gradual
weakening leading to eventual disappearance of the
conditioned response by repeatedly presenting the
conditioned stimulus (bell) without the unconditioned
stimulus (food).
• If a dog has learned to salivate at the sound of a bell, an
experimenter can gradually extinguish the dog’s response
by repeatedly ringing the bell without presenting food
afterward.
• Does it mean that the dog has forgotten what its learnt?
EXTINTION AND S. RECOVERY– cont’d
• Extinction does not mean,
however, that the dog has
simply unlearned or
forgotten the association
between the bell and the
food.
– After extinction, if the
experimenter lets a few hours
pass and then rings the bell
again, the dog will usually
salivate at the sound of the
bell once again.
• SPONTANEOUS RECOVERY
– The reappearance of an
extinguished response after
some time has passed is
called spontaneous recovery.
Graph
STIMULUS GENERALIZATION
• After an animal has learned a conditioned
response to one stimulus, it may also respond
to similar stimuli without further training.
– If a child is bitten by a large black dog, the child
may fear not only that dog, but other large dogs.
– If your lecturer slaps you and you see someone
who resembles him….?
• This phenomenon is called generalization.
–*
STIMULUS DISCRIMINATION
• The opposite of generalization is
discrimination,
– In this, an individual learns to produce a
conditioned response to one stimulus but not to
the other stimulus that is similar.
– For example, a child may show a fear response to
freely roaming dogs, but may show no fear when a
dog is on a leash or confined to a pen.
» How do we apply these principles to human? **
APPLICATION OF CLASSICAL
PRINCIPLES
• In an infamous 1921 experiment, John B. Watson and
his research assistant Rosalie Rayner conditioned a
baby named little Albert (11 month old baby) to fear a
small white rat.
– How did this happen?
– by pairing the sight of the rat with a loud noise.
• it showed for the first time that humans can learn to
fear seemingly unimportant stimuli when the stimuli
are associated with unpleasant experiences.
APPLICATION – CONT’D
• The experiment also suggested that classical
conditioning accounts for some cases of phobias,
– Phobia is an irrational or excessive fears of specific
objects or situations.
• Psychologists now know that classical conditioning
explains many emotional responses such as
– happiness,
– excitement,
– anger, and
– Anxiety, that people have to specific stimuli.
APPLICATION – CONT’D
• For example, a child who
experiences excitement on
a roller coaster may learn
to feel excited just at the
sight of a roller coaster.
• For an adult who finds a
letter from a close friend in
the mailbox,
– the mere sight of the return
address on the envelope
may elicit feelings of joy and
warmth.
APPLICATION – CONT’D
• Psychologists use classical
conditioning procedures to treat
phobias and other unwanted
behaviors, such as alcoholism and
addictions.
– In one treatment for alcoholism,
patients drink an alcoholic beverage
and then ingest a drug that produces
nausea.
– Eventually they feel nauseous at the
sight or smell of alcohol and stops
drinking it.
– AVERSIVE THERAPY (READ)
• To treat phobias of specific
objects,
• the therapist gradually and
repeatedly presents the feared
object to the patient while the
patient relaxes.
• Through extinction, the patient
loses his or her fear of the object.
• The effectiveness of these
therapies varies depending on the
individual and on the problem
behavior
APPLICATION – Contemporary views
• Modern research has also shown that conditioning
does not always require a close pairing of the two
stimuli (…beyond scope)
• In taste-aversion learning, people can develop disgust
for a specific food if they become sick after eating it,
even if the illness begins several hours after eating.
• Most associations take repeated experiences to
develop. However, one pairing with a strong
autonomic arousal can sometimes be enough to
develop a conditioned response
APPLICATION - SUMMARY
• Anxiety disorders
benefit greatly from
the following classical
strategies;
–
–
–
–
–
EXTINCTION,
COUNTER CONDITIONING,
BIOFEEDBACK,
FLOODING &
SYSTEMATIC
DESENSITIZATION.
• EXTINCTION
– Extinction happens once the CS
ceases to be associated with the
US and therefore the
conditioned response gets
extincted / eliminated.
– In Pavlov’s experiment, when
the bell no longer signaled food,
the dog eventually stopped
salivating to the bell.
– In the hospital setting, the use of
anti- nausea drugs by cancer
patients in preparation for
hospital attendance will stop the
association of hospital with
nausea and eventually
eliminates the conditioned
nausea response.
APPLICATION - SUMMARY
• COUNTER CONDITIONING
– In Counter conditioning, we
substitute a negative conditioned
response with a positive or nonharmful one.
– For example full relaxation is a
response, which opposes the
arousal of the autonomic nervous
system and can be used to
eliminate conditioned fear or
anxiety responses. Relaxation
takes time to learn though
• FLOODING
– Usually used for treatment of
phobias. Here the individual is
forcibly exposed to the situation
or object they fear until the fear
response has completely subsides.
We need great caution
(Distressing)
• BIOFEEDBACK
– This involves the use of certain
machine which has sensors which
pick up autonomic activity such as
moisture or temperature change,
or muscular tension.
– This is fed back as a continuous
but variable audible signal (like a
metal detector) to the individual.
– This feedback can enable the
individual to bring what is
normally an autonomic reflex
under voluntary control.
– Thus, the electrical activity of
muscle contraction are converted
into audible signals
– As the individual relaxes, the
signal changes. Once completed
relaxation is achieved, the signal
disappears altogether.
APPLICATION - SUMMARY
• BIOFEEDBACK
– This involves the use of certain
machine which has sensors which
pick up autonomic activity such as
moisture or temperature change, or
muscular tension.
– This is fed back as a continuous but
variable audible signal (like a metal
detector) to the individual.
– This feedback can enable the
individual to bring what is normally an
autonomic reflex under voluntary
control.
– Thus, the electrical activity of muscle
contraction are converted into
audible signals
– As the individual relaxes, the signal
changes. Once completed relaxation
is achieved, the signal disappears
altogether.
APPLICATION - SUMMARY
• SYSTEMATIC DESENSITIZATION (Wolpe,
1958)
• This is a gentler approach to
the treatment for anxieties
and phobias.
• People are first taught
relaxation technique to
counter their normal
autonomic stress response.
• They draw up a hierarchy of
anxiety provoking events
• They then learn to apply the
relaxation technique in a
hierarchical series of graded
situations from imagining a
mild fear- producing situation
to imagining a more severe
fear- producing situation, to
looking at pictures or films, to
approaching the actual
situation, then to actual
exposure.
• At each stage, the individual
must demonstrate control
through relaxation before
proceeding to the next stage.
APPLYING CLASSICAL COND.
• It is now known that human could come to fer
objects or places because they happened to be
associated with aversive experiences
– Irrational fears and other anxiety disorders
– Recent research also found relationships between
classical conditioning and immune system.
• All autonomic responses (those involving arousal of ANS) are
capable of conditioning by this type of association.
– Asthma, which is often caused by the constriction of the bronchus in response
to allergen.
• If a child has allergic reaction to cat fur, it is possible that the child may eventually
only have to see a cat in a distance to develop an asthmatic attack.
• Sometimes these types of responses may be generalized to pictures of cats or
even other animals
APPLYING CLASSICAL COND.
• Another example of conditioned reflex response is that of nausea felt
by cancer patients during the cause of drug treatment and
radiotherapy.
– Some eventually experience nausea as they approach the hospital, or even
when they just think about it.
– In other words, anything associated with the hospital is a conditioned stimulus
and nausea becomes a conditioned response.
• Finally, the principle of classical conditioning can account for fear of
doctors, hospital staff/ medical equipment.
– Example, a child who has received a painful injection may later show fer of
anyone with white coat or any clinical situation.
– The mother and staff may be unaware of the reason for this and feel that the
child is behaving irritationally.
– Have in taken notice of the fact that as a measure of punishment, parents use
injection to check certain undesirable behaviours.
APPLYING CLASSICAL COND.
• TREATMENT OF ENURESIS
– Here bell and pad (like mat) are in use
– The bell is attached to the pad and is set to sounds
as soon as soon as the first drop of urine touches
the mat.
– Upon repeated exposures the individual learns to
wake up to urinate.
LEARNING THEORIES
OPERANT CONDITIONING
DEFINING OPERANT/ SKINNERIAN/
INSTRUMENTAL CONDITIONING
• The type of learning in which behaviors are emitted (in the
presence of specific stimuli) to earn reward or avoid
punishment
• A form of learning in which the consequences of behaviour
produce changes in the probability of behavior's
occurrence… Why operant?
– Operant; describes the organism’s behaviour – behaviour
operates on the environment and the environment in turn
operate on behaviour.
– One essential element in operant conditioning is emitted
behaviour and this makes it different from classical conditioning
– Thus, unlike classical conditioning in which a response is
automatically triggered by some stimulus, (food triggers
salivation) response is spontaneous in operant, (voluntarily
studying Behavioral Science to gain marks)
OPERANT CONDITIONING – cont’d
– Voluntary spontaneous actions are called Operant behaviors
because they “OPERATE ON THE ENVIRONMENT”
– Operant conditioning is usually better than classical at explaining
VOLUNTARY behaviour
• Unlike classical conditioning, operant conditioning requires
action on the part of the learner.
• Its not like classical conditioning, in which the conditioned and
unconditioned stimuli are presented regardless of what the
learner does.
• Operant conditioning requires action on the part of the learner.
– A boy will not get his snack unless he first cleans up his room.
OPERANT CONDITIONING- cont’d
• Edward Lee Thorndike was one of the earliest American
psychologists to scientifically study animal behaviour.
– Pioneer in studying this kind of learning which involved
making a certain response because of the consequences
it brought. (NAME: Operant/ Instrumental Conditioning).
– Around the turn of the century, while Pavlov was busy
with his dogs, Thorndike (1898) was using a simple
wooden box cage “Puzzle box”*** to study how cats
learn. Procedure with hungry cats (next slide for pix)
THORDIKES PUZZLE BOX
THORNDIKE
RESULTS:
– Indicated that in the beginning it took the
cats quite a while to discover how to open
the door.
– On each trial it took them less time, until
eventually they could escape from the box
in almost no time at all.
THORDIKES PUZZLE BOX – cont’d
• DESCRIPTION
– He found that the first time an animal entered the puzzle
box, it usually took a long time to make the response
required to open the door.
– Eventually, however, it would make the appropriate
response by accident and receive its reward: escape and
food.
– As Thorndike placed the same animal in the puzzle box
again and again, it would make the correct response
more and more quickly. Soon it would take the animal
just a few seconds to earn its reward.
OPERANT CONDITIONING – cont’d
• A second essential element in operant conditioning is
the consequence of a behaviour.
– Thorndike's cats gained freedom and a piece of fish for
escaping from the puzzle boxes.
– Your dogs may receive food for sitting on command
– A child may receive praise; a chance to ride the bike or a
chance to watch TV for helping in the kitchen
• Consequences like these increase the likelihood that
a behaviour will be repeated are called REINFORCERS
• In contrast, consequences that decrease the chances
that a behaviour will be repeated are called
PUNISHERS
LAW OF EFFECT/ PRINCIPLES OF REINFORCEMENT
• Thorndike summarized the influence of consequences in his LAW OF
EFFECT as follows;
– Behavior that brings about a satisfying effect (reinforcement) is apt to
be performed again whereas
– A behavior that brings a negative effect (punishment) is apt to be
suppressed
• Another name for law of effect is PRINCIPLES OF REINFORCEMENT by
contemporary Psychologists.
– Sometimes its difficult to tell whether a particular consequence will be
reinforcing or punishing. Why?
• Candy/ toffees might be reinforcing to all children.
• Some may not like it, so for them it will not be rewarding.
• Some children whom candy is initially reinforcing may eat too much of
it, until it becomes neutral to them or even punishing.
– We must therefore be careful when identifying consequences as
reinforcers or punishers (Remember functional analysis)
SUMMARY – LAW OF EFFECT
• Behaviors that are followed by pleasant
consequences will be strengthened, and will
be more likely to occur in the future.
• Conversely, behaviors that are followed by
unpleasant consequences will be weakened,
and will be less likely to be repeated in the
future.
OPERANT CONDITIONING-
cont’d
• If we were to judge by taste, then consumers
of Guinness will consume less but that is not
the case, why?
– Obtain some reward
– Social learning ( desire to be like Michael Powell)
– Social influence (acceptance)
OPERANT CONDITIONING- cont’d
– For example, if a mother starts giving a boy his
favorite snack every day that he cleans up his
room, before long the boy may spend some time
each day cleaning his room in anticipation of the
snack.
– In this example, the boy’s room-cleaning behavior
increases because it is followed by a reward or
reinforcer.
– The next influential Scholar?
SKINNER’S RESEARCH
INTRO TO SKINNER
• PAVLOV'S VIDEOS\B.F. SKINNER A FRESH
APPRAISAL.flv
2 TERMS USED
• CONTINGENCY
– The probability that one event will follow the
other
– CONTIGUITY
• Refers to the temporal relationship between the CS and
US
• The most important factor in constiguity is the timing
SKINNER’S RESEARCH
• Skinner Box
• American psychologist B. F.
Skinner designed an
apparatus, now called a
Skinner box, that allowed him
to formulate important
principles of animal learning.
• An animal (rat, pigeon etc)
placed inside the box is
rewarded with a small bit of
food each time it makes the
desired response, such as
pressing a lever or pecking a
disc/key.
– A device outside the box
records the animal’s responses.
SKINNER’S RESEARCH
– (2) the box delivered only a
• Like Thorndike’s puzzle box,
small amount of food for each
the Skinner box was a barren
response, so that many
chamber in which an animal
reinforcers could be delivered in
could earn food by making
a single test session; and
simple responses, such as
– (3) the operant response
pressing a lever or a circular
required very little effort, so an
response key
animal could make hundreds or
thousands of responses per
• The Skinner box differed from
hour.
the puzzle box in three main
• Because of these changes,
ways:
Skinner could collect much more
– (1) upon making the desired
data, and he could observe how
response, the animal
changing the pattern of food
received food but did not
delivery affected the speed and
escape from the chamber;
pattern of an animal’s behavior.
PIGEON TAUGHT TO READ
• PAVLOV'S VIDEOS\Operant conditioning.flv
Skinners’ Pigeons playing table
tennis
• BF Skinner Foundation - Pigeon Ping Pong
Clip.flv
SKINNER’S RESEARCH
• Skinner became famous not just for his research with
animals, but also for his controversial claim that the
principles of learning he discovered using the Skinner box
also applied to the behavior of people in everyday life.
– Skinner acknowledged that many factors influence human
behavior, including heredity, basic types of learning such as
classical conditioning, and complex learned behaviors such as
language.
– he however maintained that rewards and punishments control the
great majority of human behaviors, and that the principles of
operant conditioning can explain these behaviors.
PRINCIPLES OF OPERANT CONDITIONING
• Main principles to be
considered are
– reinforcement,
– punishment,
– shaping,
– extinction,
– discrimination, and
– generalization.
• REINFORCEMENT
• Means “to strengthen”
• Is a consequence that
increases the probability
that a behaviour will
occur…Halonen and Santrock (1999:163)
• Or simply any process/
event that strengthens a
particular behavior—that
is, increases the chances
that the behavior will occur
again.
PRINCIPLES OF OPERANT CONDITIONING
•
•
TWO TYPES OF
REINFORCEMENT
– POSITIVE, & NEGATIVE
REINFORCEMENTS
Positive Reinforcement,
–
•
positive reinforcement, is a
method of strengthening
behavior by following it with
a pleasant stimulus.
Thus, a behavior is
strengthened because a
pleasant/ pleasurable
stimulus followed it.
• In experiments by Thorndike
and Skinner; bar pressing and
pecking behaviors are
followed by food pellets
which are positive
• In human, positive reinforcers
include basic items such as
food, drink, sex, and physical
comfort.
• Other positive reinforcers
include material possessions,
money, friendship, love, praise,
attention, and success in one’s
career.
!!PRINCIPLES OF OPERANT CONDITIONING
• Negative reinforcement is a method of
• Depending on the
strengthening a behavior by following it
circumstances, positive
with the removal or omission of an
reinforcement can strengthen
unpleasant stimulus.
either desirable or undesirable • There are two types of negative
reinforcement:
behaviors.
– Escape and
– Children may work hard at home
– Avoidance –ve reinforcements
or at school because of the
praise they receive from parents • In escape (already present), performing
and teachers for good
a particular behavior leads to the
performance.
removal of an unpleasant stimulus.
– For example, if a person with a
– However, they may also disrupt
headache tries a new pain reliever
a class, or start smoking because
and the headache quickly
these behaviors lead to
disappears, this person will probably
attention and approval from
use the medication again the next
their peers.
time a headache occur
PRINCIPLES OF OPERANT CONDITIONING
• Another e.g. for escape is that
your father nags at you until you
get tired/furious & you clean the
garage.
– Your (garage cleaning) response
removes the unpleasant stimulus
(nagging)
– Torture works the same way…
some lawyers or interrogators use
it a lot
– Medical Students learn in order to
avoid failure or learn in order to
obtain distinction… how do you
classify the statement??
• In Avoidance (not present
yet), people perform a
behavior to avoid
unpleasant consequences.
– For example, drivers may
take side streets to avoid
congested intersections,
– citizens may pay their taxes
to avoid fines and
penalties,
– and students may do their
homework to avoid
detention.
ADDITIONAL ILLUSTRATIONS – Reinforcements (+ve
& -ve)
• +ve reinforcement
– BEHAVIOUR
• Dress well
– CONSEQUENCE
• Compliments from loved ones/
friends
– FUTURE BEHAVIOUR
• -ve reinforcement
– BEHAVIOUR
• Taking Paracetamol
• Paying taxes
– CONSEQUENCE
• Pain removed
• Avoiding finds/ prosecution
• Dressing behaviour increases
– FUTURE BEHAVIOUR
• Para taking behaviour increases
• Tax paying increases
How do you distinguish between
Reinforcement and Punishment?
Before then, what is Punishment?
PRINCIPLES OF OPERANT CONDITIONING
• Punishment
– Is any event whose presence
decreases the likelihood that
ongoing behaviour will recur.
– Or any event which when made
contingent on a behaviour
decreases the likelihood that that
behaviour will recur.
• there are two kinds of punishment,
positive and negative.
• Positive punishment involves
reducing a behavior by delivering an
unpleasant stimulus if the behavior
occurs.
– Parents use positive punishment
when they spank, scold, or shout
at children for bad behavior.
• Societies use positive punishment
when they fine or imprison people
who break the law. (rules in the
universities !!)
• Negative punishment, also called
omission,
– involves reducing a behavior by
removing a pleasant stimulus if
the behavior occurs.
– Parents’ tactics of grounding
teenagers or taking away various
privileges because of bad behavior
are examples of negative
punishment.
– Is punishment an effective means of
controlling behaviour?
PRINCIPLES OF OPERANT CONDITIONING
• Experiments have shown that, • Punishment may eliminate
when used properly,
desirable behaviors along with
punishment can be a powerful
undesirable ones.
and effective method for
– For example, a child who is scolded
reducing behavior.
for making an error in the classroom
may not raise his or her hand again.
• There are however some
• May sometimes only minimize it and
disadvantages;
not eliminate it (e.g. Drivers &
– become angry, aggressive, or
highway police patrols).
have other negative emotional
• For these and other reasons, many
reactions.
psychologists recommend that
– Does not teach the right
punishment be used to control
behaviour
behavior only when there is no
– May have some negative
realistic alternative.
physical problems (hurt)
DISTINCTION BETWEEN REINFORMENT
AND PUNISHMENT
• REINFORCEMENT
– Whether positive or
negative results in an
increase in behaviour.
– For human, money, grades, hugs,
kisses, praise and pat on the back
are good examples.
– Even an electric shock could be
reinforcer.
• Olds and Milners, 1954; Wise
1996 and Rolls, 1999 used
MILD ELECTRICAL stimulation
to in certain “ Pleasure
centers” of the brain,
• some of the animals chose to
apply electric shock although
they were very hungry
• PUNISHMENT
– Whether negative or
positive results in decrease
in behaviour
• Negative reinforcement is also
known as ESCAPE LEARNING OR
AVOIDANCE LEARNING, because
the responses lead to escape from
or avoidance of some unpleasant
events.
LIVER PRESSING IN RAT
• PAVLOV'S VIDEOS\Conditioned suppression of
a rat's lever pressing.flv
PRINCIPLES CONT’D; …SHAPING
• Shaping is a reinforcement
technique that is used to teach
animals or people behaviors that they
have never performed before.
– The method (Successive
approximation) is used whereby
the teacher begins by reinforcing
a response the learner can
perform easily, and then gradually
requires more and more difficult
responses
– For example, to teach a rat to
press a lever that is over its head,
the trainer can first reward any
upward head movement, then an
upward movement of at least one
inch, then two inches, and so on,
until the rat reaches the lever.
– Skinner used it to teach pigeons to
play pin- pong
• Psychologists have used
shaping to teach children with
severe mental retardation
– to speak by first rewarding any
sounds they make, and then
gradually requiring sounds that
more and more closely
resemble the words of the
teacher.
• Animal trainers use shaping to
teach
– elephants to stand on one leg,
– tigers to balance on a ball, &
– killer whales and dolphins to
jump through hoops/play
football etc.
PRINCIPLES CONT’D; …SHAPING
SHAPING & CHAINING
• CHAINING BEHAVIOUR
– To produce more complex
sequence of behaviour,
Psychologists use a procedure
called chaining. The process is
similar to shaping
• what does the trainer do?
– First, the animal learns the final
behaviour for some
reinforcements; then it learns
the next- to- last behaviour,
which is reinforced by the
opportunity to perform the final
behaviour. And so on.
– A simplified example of
response chaining is provided by
Barnabus, a rat trained by
psychologists Pierrel and
Sherman, (1963) at Brown
university.
• By carefully working from the
last response to the first,
Barnabus was trained to make
an ever-longer chain of
responses to obtain a single
food pellet.
• When in top form, Barnabus
was able to
–
–
–
–
–
–
–
–
–
–
–
climb a spiral staircase,
cross a narrow bridge,
climb a ladder,
pull a toy car with chain,
get into the car,
pedal it to a second staircase,
climb the staircase,
wriggle through a tube,
climb onto an elevator and
descend to a platform,
press a lever to receive a food
pellet, and…start all over.
SUPERSTITIOUS BEHAVIOUR
• Reinforcement affects not only
the last response we are
interested in, but also other
responses occurring shortly
before.
• This helps account for learning
of many human superstitions.
– If a golfer taps her club on the
ground three times and then
hits an unusually fine shot, the
success of the shot reinforces
not the correct swing but also
the three taps.
– It happens in other sporting
activities as well.
– If Kotoko/ Hearts went for Juju
and they won, they are likely to
go for another one before a
crucial encounter in which they
wish to win
• During operant training,
animals often develop similar
unnecessary responses.
– If a rat scratches its ear just before
its bar press, it may continue to
scratch its ear before ensuring bar
press.
• In this case, the bar press is all
that is needed to produce food,
but the animal may continue to
“superstitiously” scratch its ear
each time, as if this were also
necessary.
STIMULUS GENERALIZATION,
DISCRIMINATION & EXTINCTION
SAME AS IN CLASSICAL
CONDITIONING … PLEASE READ !!!
APPLICATION OF OPERANT
CONDITIONING
• Operant conditioning techniques have practical
applications in many areas of human life.
– Parents who understand the basic principles of operant
conditioning can reinforce their children’s appropriate
behaviors and punish inappropriate ones, and they can use
generalization and discrimination techniques to teach
which behaviors are appropriate in particular situations.
– In the classroom, many teachers reinforce good academic
performance with small rewards or privileges.
– Companies have used it to improve attendance,
productivity, and job safety among their employees.
APPLICATION OF OPERANT CONDITIONING
• Behavior therapists use shaping techniques to teach
basic job skills to adults with mental retardation.
– Therapists use reinforcement techniques to teach self-care
skills to people with severe mental illnesses, such as
schizophrenia,
– and use punishment and extinction to reduce aggressive and
antisocial behaviors by these individuals.
• Psychologists also use operant conditioning techniques to
treat drug addictions, stuttering, sexual disorders, marital
problems, impulsive spending, eating disorders, and many
other behavioral problems
APPLICATION OF OPERANT CONDITIONING
• USE OF OPERANT CONDITIONING IN PSYCHIATRIC
HOSPITAL
• Token Economy is the name if a common form of
contingency contracting used in Psychiatric hospital.
In Token economy the resident patients who perform
desired activities earn plastic chips that can later be
exchanged for some tangible benefit. It could also be
used by psychotherapists to reinforce their clients.
APPLICATION OF OPERANT
CONDITIONING
• Behavior Modification, psychological methods for
treating maladjustment and for changing observable
behavior patterns.
• A landmark event for behavior modification took
place when Pavlov's conditioning principles were
extended to humans.
– !!! In 1920 the American psychologists John B. Watson and
Rosalie Rayner reported an experimental study in which an
11-month-old baby who had previously played with a
white laboratory rat was conditioned to be fearful of the
rat by associating a loud noise with the animal, a process
known as pairing. !!!CLASSICAL
APPLICATION OF OPERANT
CONDITIONING
• The psychologist Mary Cover Jones later performed
experiments designed to reduce already established
fears in children.
• She found two methods particularly effective:
– (1) associating a feared object with a different stimulus
capable of arousing a positive reaction, and
– (2) placing the child who feared a certain object with other
children who did not.
• This method is in use today by lots and lots of
therapists where the child is reinforced after
performing the desired response
APPLICATION OF LEARNING THEORIES
• Aversion therapy is used to break disabling bad
habits.
– An aversive stimulus, such as an electric shock, is
given together with the “bad habit,” such as an
alcoholic drink.
– Repeated pairings result in changing the values of
such stimuli from positive attraction to repulsion…
operant
APPLICATION OF OPERANT CONDITIONING
• Applied behavior analysis is
used to develop educational
and treatment techniques for
individuals people in need
• Example of these individuals
may include
– retarded or disturbed
children in a school or
residential setting,
– or adults in a psychiatric
hospital or rehabilitation
center.
• Five essential steps must be
considered:
– (1) deciding what the individual can
do to ameliorate the problem;
– (2) devising a program to weaken
undesirable behavior and
strengthen desirable substitute
behavior;
– (3) carrying out the treatment
program according to behavioral
principles;
– (4) keeping careful and objective
records; and
– (5) altering the program if progress
can thereby be improved.
ASSIGNMENTS
• Compare classical and operant conditionings
• Summarize the Cognitive views/
interpretations of Learning theories
• SCHEDULES OF REINFORCEMENTS
COMPARISON OF CLASSICAL & OPERANT CONDITIONING
CLASSICAL CONDITION
OPERANT CONDITION
1.Nature of Response
Involuntary, reflex
Spontaneous Voluntary
2. Reinforcement
Occurs
before
response Occurs after response
(conditioned stimulus pared (Response is followed by
with UCS)
reinforcing stimulus or
events.
3. Role of Learner
Passive (Response is elicited Occurs after response
by US)
(active
response
is
followed by reinforcing
stimulus or events.
4. Nature of Leaning
Neutral stimulus becomes a C. Probability of making a
S through association with an response is altered by
UCS.
consequence at follows it.
ADDITIONAL INFORMATION OF
REINFORCEMENT
SCHEDULES OF REINFORMENTS
SCHEDULES OF REINFORCEMENTS
• Continuous reinforcement = a schedule of reinforcement in which every occurrence
of a particular response is reinforced.
• Partial Reinforcement = a situation in which the occurrence of response is
sometimes followed by a reinforcement.
• Skinner (1956)
– Found that specific preset arrangements of partial reinforcement produced different
patterns and rates of responding.
– Together, these different reinforcement arrangements are called SCHEDULES OF
REINFORCEMENT (is the delivery of reinforcer according to a preset pattern based on
the number of responses or the time interval between responses).
• There are four types of schedules
–
–
–
–
FIXED RATIO
VARIABLE RATION
FIXED – INTERVAL SCHEDULE
VARIABLE INTERVAL
SCHEDULES OF REINFORCEMENTS
• FIXED RATIO (FR).
– Reinforcement occurs after a fixed
number of responses
• Example
– Rat on 25 – to – 1 fixed ratio
abbreviated FR 25) may have to press
the bar 25 times in order to receive
one food pellet.
– Shaping is needed first; i. e the cat
may have to be put on FR – 2, FR – 4
etc before FR – 25.
• EVERYDAY LIFE example
– Work for which you are paid for
producing a specific number of items;
– Paid ¢100 for producing a number of
items (blocks, ice water etc)
• VARIABLE – RATIO
– Occurs when after an average
number of responses, which
varies from trial to trial.
• Examples
– A rat on a variable ratio – 20
schedule (VR – 20) would be
reinforced after an average of 20
responses; presses 25 at first and
15 bar presses later before being
reinforced.
– Number of trials are
unpredictable but over time
repeated trials, the ratio of
responses to reinforcers work out
to predetermined averages.
VARIABLE RATIO – CONT’D
• This V – R – S produces high steady rates of responding
with hardly any pauses b/n trials of after reinforcement.
• Why do VRS produce such persistence responses?
– One explanation is that although its impossible to predict
which response will result in reinforcement; the more
responses that are made the greater the likelihood of
reinforcement.
– The combination of the two factors can make some
behaviors, such as gambling “ addictive” for some people.
– Everyday example; toss of a dice, purchase of lottery ticket.
The more u gamble, the more the opportunity.
SCHEDULES OF REINFORCEMENTS
– F I S. produces a pattern of
• FIXED – INTERVAL (F.I) (interval
responding in which the number of
responses tend to increase as the
time for the next reinforcer draws
near.
means reinforcement depends on passage of
time instead of number of responses)
– Reinforcement is delivered for the
1st response emitted after the
preset time interval has elapsed.
– A rat put on two – minute fixed
interval schedule (FI – 2 min.)
would receive no food pellet for
any bar presses made during the
first two minutes, whether it
presses the bar twice or 100
times.
– But the first bar press after the
2nd – minute interval has elapsed
would be reinforced.
•
A rat on F. I – 10 minute schedule may go
for several minutes without pressing the
bar. As the 10th minute draws near it starts
the bar pressing behavior vigorously.
•
DAILY LIFE EXAMPLE
– If your lecturer organizes a quiz/ test every
month ending, most students would wait a
while and start to learn at the end of the
month.
– After test studying behavior drops.
SCHEDULES OF REINFORCEMENTS
• VARIABLE INTERVAL
– Reinforcement occurs for the first
response emitted after an average
amount of time has elapsed, but
the interval varies from trial to
trial.
– Length of time that must pass
before reinforcement is delivered
is unpredictable, but over a series
of trials, it works out to be a
predetermined average.
– A rat on a V – I 30 seconds
schedule might be reinforced on
trial for the first bar press after
only 20 seconds have elapsed, for
the first bar press,
– 1st after 50 seconds have elapsed on
trial 2, and for the first bar press after
30 seconds have elapsed on trial 3.
• This works out to an average of one
reinforcement every 30 seconds.
• Generally, the unpredictable nature
tends to produce, moderate but
steady rates of responding esp. when
the average is relatively short.
• Another e.g; trying to call a friend
from GT to Space or vice versa – you
try periodically but impossible to
predict.
SCHEDULES OF REINFORCEMENTS