Transcript learning behavior

LEARNING
BEHAVIOR
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Animal behavior
Refers to the activities
animals perform during their lifetime,
including locomotion, feeding,
breeding, capture of prey, avoidance of
predators, and social behavior. Animals
send signals, respond to signals or
stimuli, carry out maintenance
behavior, mate choices, and interact
with one another.
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Animal behavior relates to what
an animal does and why it does it.
The types of behaviors exhibited
by animals are rich and various.
Some are genetically determined,
or instinctive, while others are
learned behaviors.
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Instinctive behaviors/Fixed
Action Pattern:Much of early
research on animal behaviour was
governed by the idea that animals, as
opposed to humans, were largely guided
by “instinctive” behaviour, where
stimulus-response patterns are
genetically pre-programmed and hard
wired into the nervous system
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EXAMPLE
web making by spiders is an
example of a genetically determined or
instinctive behavior. There is little variation
between individuals in how they construct the
web and it is constructed similarly each time
they do it. Ethologists (people who study
behavior) call such a behavior a fixed action
pattern. Fixed action patterns do not require
learning or prior experience for their
expression. They can, however, be very
complex
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EXAMPLE
Egg Rolling in Graylag Goose
Fixed Action Pattern
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Learning Behaviors
Learning and memory are two sides
of a coin. A number of surprising
findings have lead researchers to
believe that virtually everything we
encounter is learned and is stored
away in the brain
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LEARNING
Is the modification
of behavior in response to
specific experiences.
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 Learning involves a change in behavior, often
long lasting. It is not passed on to the next
generation.
 Learning is characterized by persistent and
measurable changes in behavior which are not
associated with fatigue, altered motivation, or
maturation.
 Some information or knowledge is acquired
and is then used to alter the individual’s actions
and responses.
 Learning as an adaptive behavior allows
individuals to adapt to specific environment
challenges.
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Types of Learning
According to Thorpe types of learning are given below.
1). Flexible.
•Habituation
(non associative learning)
•Classical conditioning (associative learning)
•Trial and error
(associative learning)
• Latent
(associative learning)
•Discrimination
(associative learning)
2). Restricted.
•Imprinting
(associative learning)
•Reasoning and insight (associative learning)
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Flexible learning
1. Habituation: It is the decrease in
response to repeated or continuous
stimulation or, it is the gradual fading of
a response when a stimulus that proves
to be safe, neutral or irrelevant is given
repeatedly.
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Habituation is the simplest form of learning.
 Habituation like phenomena is found in every
group of animals from Weevil to Whales.
By habituation animals learn to conserve energy
and time by not responding to an irrelevant
stimulus.
If a neutral stimulus that has neither noxious
nor beneficial consequences is repeatedly delivered
to an organism, its response to the stimulus tends
to decrease gradually and may eventually cease all
together. By habituation animals learn, what not to
do.
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Habituation is considered distinct from
Fatigue and Sensory adaptation.
Habituation has been reported to have
correlation with a' change in Central
Nervous System.
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Example 1
A Spider is sitting in its web. The
experimenter vibrates point on its web,
resembling the signal set up when an insect is
trapped. The spider runs out to investigate the
source of the vibration, nothing is found and
spider returns to its place in the, centre of the
web. If this same neutral stimulus is given
several times, the spider no longer rushes out to
investigate. It remains in the centre of the web.
It gets habituated to that stimulus
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Example 2
A Snail crawling across a sheet of glass
retracts into its Shell when the glass is tapped.
After a pause it emerges and continues
moving. A second tap causes retraction again
but it emerges quickly, frequent tapping on
glass ultimately cause no response at all in
snail and it will keep on moving. This is due to
habituation.
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Example 3
In the lab, Clark could easily get the Nereis to live in
glass tubes. He found that mechanical stimuli like
tapping on the tube or touching the head of the
worm or even a sudden shadow passing over
caused a rapid retraction into the tube, but the
majority of worms emerged again within a minute.
If these stimuli were repeated at 1 minute intervals
the percentage of worms responding fell until none
of them were retracting. Clark concluded that
Nereis got habituated to the stimuli.
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Example 4
Hydra has a long, slender body, and its still longer
fine tentacles (Fig. 1d) sweep the water. A sudden
increase In light, or a mechanical disturbance, can
cause general contraction. In one experiment,
hydra were mechanically touched on tentacles
without a harm or benefit the number of hydra
responding to this gentle touch declined
indicating habituation.
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Dishabituation
It has been experimentally proved that "the
effect of repeated stimulation of one kind is
cancelled by a new stimulus of another kind and
this is called "Dishabituation".
Example
once hydra was habituated with soft
mechanical touch, it responded to another kind
of stimulus say a fish of light.
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2. Classical conditioning: The term
conditioned reflex is inseparable from the names of
Great Russian physiologists I.P. Pavlov (l941) and
Sherrington (1942).
Reflexes :This term implies an automatic
adjustment to maintain homeostasis without
conscious effort.
There are two types of reflexes
• A simple reflex
•A conditioned reflex
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A simple reflex is the simplest automatic
functional unit of the nervous system capable
of detecting change and cause a response to
that change. Simple reflex are also known as
inborn or unconditioned reflexes, fixed or
inherited like the knee jerk, closing of eyes.
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Conditioned or acquired reflexes:
(I) Are acquired in life, are not transmitted
through genes.
(II) They can be established or abolished.
(III)They are always established upon some preexisting unconditioned reflexes.
These are flexible and steer animals through their
changing environments by means of signs, sounds,
smells.
According to Pavlov, all kinds of habits arising
from training, education and discipline are due to
chain of conditioned reflexes.
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Conditioned Stimulus & Conditioned
Response:
Food stimulates salivary secretion This is
an unconditioned reflex. Now, if a second stimulus
like ringing of bell be applied just before giving of
food, for some days, the bell sound will be able to
elicit salivary reflex, even if no food is given. Such a
stimulus is called conditioned stimulus and salivary
secretion is conditioned response (CR).
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Example 1
Famous experiment of Pavlov with dog
involved the salivary reflex. Dogs salivate when
food is put into their mouths and Pavlov could
measure the amount of saliva secreted, by
inserting a fistula, through the cheek to the
salivary duct, so that drops of saliva fell into a
funnel and could be counted. A hungry dog was
placed on a stand; dog was given meat powder
that caused secretion of saliva. Pavlov rung a bell
just prior to feeding, at first this stimulus caused
no response,
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after repeating the same thing for 5-6 times, saliva
began to drip from the fistula soon after the hearing
of bell even before the meat powder arrived.
Eventually, the saliva was produced after hearing the
bell alone. The dog had learnt to respond to a new
stimulus which was previously "neutral" and Pavlov'
called this the Conditioned Stimulus (CS). The
salivation response to CS is the Conditioned
Response (CR). Prior to this learning, only the meat
powder or Unconditioned Stimulus (UCS) was
producing salivation or Unconditioned Response
(UCR).
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Positive reinforcement The stimulation
that follows with a reward is called positive
reinforcement
Negative reinforcement When
stimulation is associated with punishment -it is
termed as negative reinforcement.
Pavlov had used positive reinforcement.
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Example
In another experiment, an electric Shock (UCS)
causes a dog to lift its paw (UCR), if a bell is rung
(CS) just prior to UCS, the dog learns to raise its
paw just after hearing the bell (CR). Here the CR is
associated with punishment or negative
reinforcement.
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Example2
Karl Von Frisch kept a dwarf Sheat fish that
lived in a small tube at the bottom of its
aquarium. Von Frisch fed the animals by holding
the food (UCS) close to the tube and the fish
quickly left its shelter (UCR) to eat it. One day he
began to accompany feeding, with whistling, the
fish had never responded to whistle before. But 5
days after, Von Frisch when whistled (CS) before
feeding the fish came out of her tube to eat (CR),
they got conditioned to whistling.
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Example 3
Classical conditioning is clearly a natural
phenomenon with real biological value. The
animals learn to associate the presence of prey or
predator with other normally occurring stimuli. The
deer flee (UCR) at the sight of a tiger (UCS). When a
tiger is moving towards a herd-the monkeys whoop,
the birds make noises and these act as conditioned
stimuli (CS) -and soon, just after hearing the alarm
calls (CS) from monkey and birds the deer flee
(UCR).
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3. Trial and error or instrumental
or operant learning
a. This learning is called trial and error because in
this animal tries again and again to achieve the
goal, keeps eliminating errors and one day
learns to perform it without any error.
b. It is also called instrumental because animals
were allowed to perform in an instrument.
c. it is also called operant because animal
operates upon surroundings.
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Conditioned learning is associated with unconditioned
stimulus and response, whereas; trial and error has
basic instincts and motivation (drive or urge) at the
base. When animals are motivated by thirst, hunger, sex
or fear they show restlessness, and exploratory or
appetitive behavior during the course of which it
performs spontaneously a variety of motor patterns vizsniffing, walking and looking around. If one of these
patterns is followed by reinforcement
e.g. a hungry animal while exploring the surroundings
receives food and if this association is repeated the
animal learns to perform a pattern regularly to that
particular situation.
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Example 1
An example will make it clear why
this type of learning is called trial and error. In this
experiment on learning Thorndike used, a
problem box. This puzzle box, also called
Thorndike box is a cage that can be opened from
inside by depressing a lever. A cat is shut in, which
tries hard to escape, it moves around restlessly,
explores its surroundings, bangs its head and paw
here and there to somehow open the box, after
sometime, by chance it steps on the lever and the
door opens.
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The second trial is the repetition of first, and the
third, soon the cat concentrates more attention
on the lever and eventually it moves swiftly across
the box and presses the lever as soon as it is
confined. The cat learns to eliminate behavior that
led to no reward and increases the frequency of
behavior which was rewarding. The first reward
was obtained by pure chance.
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Experiment 2
Trial and error learning is not confined to
animals with, well developed brains. It is also
shown even by smaller creatures like
earthworms. An earthworm is placed in the
stem of T-shaped tube. If it turns left it is given
the electric shock, if it turns right it is returned
to its box without punishment. It is claimed by
scientists that the worm learns by trial and
error to associate turning left with punishment
and eventually always turns right
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Example 3
A classical example of instrumental
conditioning is that of a rat in Skinner box
developed by Skinner (1904-1990), a prominent
physiologist. When placed in a box, the rat begins
explore it moves all about the box and, by accident,
eventually presses a lever and is rewarded with a
food pellet. Because food rewards are provided
each time the rat presses the lever, the rat associate
the reward with the behavior. Through repetition,
the rat learns to press the lever right away to
receive reward.
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In this type of learning, the animal is instrumental in
providing its own reinforcement
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Experiment 4
An octopus is seen (in fig) leaving its shelter and
advancing towards the crab at the other end of its tank.
It faces two situations.
1. If it attacks the crab whose nearby a square is
hanging, the octopus receives an
electric shock.
2. In another situation, there was no square i.e. the
electric plates was removed and octopus is allowed
to attack the crab i.e. without getting an electric
shock. After a few days, by trial and error, the
octopus learns to attack when the crab is alone and
does not attack the crab when an electric plate is
hanging nearby.
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Prepared by:-
AMAAN ALI
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