Transcript psych powerpoint

Chapter 8
Learning
James Henderson
Robert Reed
Shalom Aziague
Denise Delagarza
Seth Ewing-Hendrick
Classical
Conditioning
Classical conditioning
 More
than 200 years ago, philosophers
such as John Locke and David Hume
echoed Aristotle's conclusion from 2000
years earlier. We learn by association
 our minds naturally connect events that
occur in sequence.
 Example: If you associate a sound with a
frightening consequence, then your fear
may be aroused by the sound itself
Cont..





By linking two events that occur close together,
both the sea snail and the seal exhibit associate
learning.
Conditioning is the process of learning association
In classical conditioning, we learn to associate two
stimuli and thus to anticipate events.
We learn that a flash of lightning signals an
impending crack of thunder ,and so we start to
brace ourselves when lightning strikes nearby
In operant conditioning, we learn to associate a
response (our behavior) and its consequences
and thus to repeat acts followed by good results
and avoid acts followed by bad results.
Classical conditioning



Ivan Pavlov performed experiments that are
considered classical conditioning
Another important psychologist that dealt
with classical conditioning was John B.
Watson.
John’s idea was that psychology should study
how organisms respond to stimuli in their
environments. He thought that psychology
should be an objective science based on
observable behavior which is called
behaviorism
Pavlov experiment






After studying salivary secretion in dogs ,he knew that when he
put food in a dog’s mouth, the animal would invariably salivate
The repeated behavior could make the dog salivate with the
mere sight of the food, the smell of the food or even the person
who brought it
Because salivation in response to food in the mouth was
unlearned, Pavlov called it an unconditional response (UR).
Food in the mouth automatically, unconditionally triggers a
dog’s salivary reflex. Thus Pavlov called the food stimulus and
unconditioned stimulus (US).
One translation of Pavlov therefore calls the salivation the
conditional reflex. Today we call this learned response the
conditional response (CR).
The permissibly irrelevant tone stimulus that now triggered the
conditional salivation we call the conditional stimulus (CS).
Acquisition(Initial learning)




To understand acquisition of the stimulus –response relationship, Pavlov
and his associates first had to confront the question of timing.
Although it’s not likely for conditioning to occur, it could occur when the
CS follow the US. This finding fits the presumption that classical
conditioning is biologically adaptive. It helps organisms prepare for
good or bad events.
Michael Domjan Showed how the CS signal are important biological
event by conditioning the sexual arousal of male Japanese quail
Ex: Just before presenting an approachable female, the researchers
turned on a red light, over time ,the red light announced the arrival of
the female quail, which caused the male quail to because sexually
aroused and copulate with her more quickly when she arrived.
Moreover, the quail grew to enjoy the red-light district of the cage.
Exposure to the sexually conditioned stimuli also caused them to release
more semen and sperm. The quail’s capacity for classical conditioning
gives it a reproductive edge.
Extinction and spontaneous
recovery
 According
to Pavlov experiment, when he
sounded the tone again and again
without presenting food, the dogs
salivated less and less. The declining
salivation illustrates extinction.
 If allowed several hours to elapse before
sounding the tone again, the salivation to
the tone would reappear spontaneously
Generalization



Pavlov and his students noticed that a dog
conditioned to the sound of one tone also
responded somewhat to the sound of a
different tone never paired with food.
The tendency to respond to stimuli similar to
the CS is called generalization
Example: generalization can be adaptive, as
when toddlers taught to fear moving cars in
the street respond similarly to trucks and
motorcycles.
Discrimination
 Pavlov
dogs also learned to respond to
the sound of a particular tone and not to
other tones.
 Like dog generalization, discrimination has
survival value. Slightly different stimuli are
at time followed by vastly different
consequences
Extending Pavlov’s
understanding
 Pavlov’s
and Watson’s Disdain for
“mentalist” concepts such as
consciousness has given way to a
growing realization that they
underestimated the importance of
cognitive processes(thoughts,
perceptions , expectations)and biological
constraints on an organism’s learning
capacity
Cognitive processes



Robert Rescorla and Allan Wagner argued that
when two significant events occur close together
in time, an animal learns the predictability of the
second event.
An example of this is if a shock is always precede
by a tone, and then sometimes also by a light that
accompanies the tone, a rat will react with fear to
the tone but not to the light. Although the light is
followed by the shock ,it adds no new information;
the tone better predicts the impending shock.
That principle helps explain why classical
conditioning treatments that ignore cognition
often have limited success.
Biological predispositions

Ever since Darwin, scientists have assumed that all
animals share a common evolutionary history and
resulting commonalities in their makeup and
functionality. Pavlov and Watson believed the
basic laws of learning were essentially similar in all
animals, so it should make a little difference
between pigeons and humans. More than the
early behaviorists realized, an animals capacity for
conditioning is constrained by its biology. Each
species' predispositions prepare it to learn the
associations that enhance its survival.
Operant
Conditioning
Operant Conditioning
 Operant
conditioning explains and trains
behaviors such as an elephant walking on
its hind legs or a child saying please.
 Classical and operant conditioning
include acquisition, extinction,
spontaneous recovery, generalization,
and discrimination.
 Operant behavior produces rewarding or
punishing stimuli (consequences).
Skinner’s Experiments



B. F. Skinner was a college English major and an
aspiring writer who, seeking a new direction, entered
graduate school in psychology. He went on to
become modern behaviorism’s most influential and
controversial figure. His work elaborated a simple
fact of life that psychologist Edward L. Thorndike
called the law of effect, which stated rewarded
behavior is likely to recur.
He used the law of effect as a starting point and
developed a “behavioral technology” that revealed
principles of behavior control.
These principles allowed him to teach pigeons unpigeon like behavior such as walking in a figure 8,
playing Ping-Pong, and keeping a missile on course
by pecking at a target on a screen.
Skinner’s Experiments cont.


Skinner designed an operant chamber, known as a
Skinner Box which he used for his studies with rats and
eventually pigeons.
The box has a bar or key that an animal presses or pecks
at to release a reward of food or water, and a device
that records these responses.
Shaping Behavior
 Uses
reinforcers, such as food, to guide an
animal’s actions toward a desired
behavior.
 Makes the animal get closer and closer to
where you want and rewards them.
 Sometimes we as humans reward
annoying behaviors unintentionally.
Types of Reinforcers




Positive reinforcement strengthens a response
by presenting a typically pleasurable stimulus
after a response.
Positive reinforcers include: praise, attention,
hugs, food, etc.
Negative reinforcement strengthens a
response by reducing or removing an aversive
(undesirable) stimulus.
Negative reinforcers include: taking aspirin to
relieve a headache and pushing the snooze
button to silence an annoying alarm clock.
Primary and Conditioned
Reinforcers
 Primary
reinforcers, such as getting food
when hungry or being relieved of electric
shock, are innately satisfying.
 Conditioned reinforcers, also known as
secondary reinforcers, are learned. They
get their power through their association
with primary reinforcers. Such as if a rat in
a Skinner box learns that a light reliably
signals that food is coming, the rat will
work to turn on the light.
Immediate and Delayed
Reinforcers



Rats do not respond well to delayed reinforcers. The
rat in a Skinner box will engage in “unwanted”
behavior (scratching, sniffing, and moving around)
before performing the “wanted” behavior to receive
the reward.
If the rat presses the bar, but if the researcher is
distracted and delays the reinforcer for longer than
30 seconds, the rat will not learn to press the bar.
Unlike rats, humans do respond to reinforcers that are
greatly delayed: the paycheck at the end of the
week, the good grade at the end of the semester. To
function effectively we must learn to postpone
immediate rewards for greater long-term reward.
Reinforcement Schedules


Many of the previous examples assume continuous
reinforcement: The desired response is reinforced
every time it occurs. Under these conditions, learning
occurs rapidly, but so does extinction.
Real life does not often provide continuous
reinforcement, so why do people do the things they
do? They do it because their efforts have
occasionally been rewarded. This is called partial
(intermittent) reinforcement schedule, in which the
responses are sometimes reinforced, sometimes not.
Initial learning is slower with intermittent
reinforcement, but it produces greater persistencegreater resistance to extinction.
Reinforcement Schedules
cont.




Fixed-ratio schedules reinforce behavior after a set
number of responses much like people paid on a
piecework basis.
Variable-ratio schedules provide reinforcers after
an unpredictable number of responses. This is what
gamblers experience and why it is so hard to
extinguish.
Fixed-interval schedules reinforce the first response
after a fixed time period. Like people checking
more frequently for the mail as the delivery time
approaches.
Variable-interval schedules reinforce the first
response after varying time intervals.
Punishment



The effect of punishment is opposite to that of
reinforcement. Punishment decreases a behavior, thus a
punisher is any consequence that decreases the frequency
of a preceding behavior, usually by administering an
undesirable consequence or withdrawing a desirable one.
Physical punishment may increase aggressiveness by
demonstrating that aggression is a way to cope with
problems. This helps explain why so many aggressive
delinquents and abusive parents come from abusive
families.
Even though punishment suppresses unwanted behavior, it
often does not guide one toward more desirable behavior.
Punishment tells you what not to do; reinforcement tells you
what to do.
Latent Learning


Rats exploring a maze, with no obvious
reward, are like people sightseeing in a new
town. The rats seem to develop a cognitive
map, a mental representation of the maze.
When an experimenter then places a reward
in the maze’s goal box, the rats very quickly
perform as well as rats that have been
reinforced with food for running the maze.
During their explorations, the rats seemingly
experience latent learning, learning that
becomes apparent only when there is some
incentive to demonstrate it.
Intrinsic Motivation
 Excessive
rewards can undermine intrinsic
motivation, the desire to perform a
behavior effectively and for its own sake.
Intrinsically motivated people work and
play in search of enjoyment, interest, selfexpression, or challenge. Extrinsic
motivation is the desire to behave in
certain ways to receive external rewards
or avoid threatened punishment.
Skinner’s Legacy
 Applications
of operant conditioning can
be seen at school, in sports, at work, and
at home.
Contrasting Classical and
Operant Conditioning
 Both
classical and operant conditioning
are forms of associative learning
 Classical conditioning is when an
organism associates different stimuli that it
has no control over and responds to it.
 Through operant conditioning, an
organism associates operant behaviors
with their consequences.
Learning by Observation







Not all learning needs to occur through direct
experience
Observational learning is when we observe and
imitate others
This learning type also applies to other species
Cultural elements gained through imitation are
called memes
Mirror neurons provide a neural basis for
observational learning
Mirror neurons also serve language, help children
learn how to mime lip and tongue movements when
forming new words.
They also allow us to infer another’s mental state
Bandura’s Experiments





While a child is in the room, an adult beats a Bobo
boll for a long period of time. Later when the kid is
frustrated and left alone, he also attacks the Bobo
doll using the same words the adult used.
Watching the doll be beaten lowered the child’s
inhibitions
What determines what we imitate are
reinforcements and punishments
By looking we can determine a behaviors
consequences
We are more likely to imitate those we see as
similar to ourselves as successful or as admirable
Applications of Observable
Learning








Anti-social models may have anti-social effects
Some learned things are that physical intimidation is effective
and free and easy sex is pleasurable with no consequences.
Also explains how abusive parents have aggressive kids and
wife-battering fathers had parents who battered others.
Lessons learned as children are not easily forgotten
Pro-social models can have positive effects on others
Parents re also powerful models
Those exposed to a hypocrite model tend to become
hypocrites themselves
Television is a huge source of observational learning seeing as
most children when they are 18 watch more television than
they spend in school
Applications of Observable
Learning cont.







T.V. allows for spread of culture between different countries
Television portrays the real world poorly
Before finishing elementary school, the average child has
seen 8000 television murders and 100000 other acts of
violence
Violence is in 6 in every 10 programs, 78% goes unpunished,
58% did not show victims pain, and nearly half is seen as
justified.
The more media violence a child sees, the more often they
get into fights
The more violence watched, the more at risk they are for
aggression and crime
Homicide rates doubled between 1957 and 1974 when
television was introduced
Applications of Observational
Learning cont.




While there is a correlation, it does not prove
causation
There is a possibility that violent programs
reflect violent behavior, not that it causes it
The scientific community believes media
violence is a cause of violence, especially if
caused by an attractive person who goes
unpunished and causes no visible pain or
harm.
Prolonged exposure to violence desensitizes
viewers