Transcript Individual learning

Chap.04 Learning
鄭先祐 (Ayo) 教授
國立台南大學 環境與生態學院
生態科學與技術學系
環境生態研究所 + 生態旅遊研究所
Learning
What is individual learning?
How animals learn
Why animals learn
What animals learn
Molecular genetics and endocrinology
of learning
Phylogeny and the neurobiology of
learning
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Damselflies
larvae learn
about
predation
threat through
chemical cues.
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What is individual learning?
Individual learning, to a relatively
permanent change in behavior as a
result of experience.
Phenotypic plasticity, an organism to
produce different phenotypes
depending on environmental conditions.
 In some bryozoans, colonies produce
spines when predators are present. (A)
spines are shown protruding from a colony.
(B) an overview of a colony (Fig. 4-3)
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When colonies of the bryozoan are exposed to chemical
stimuli from a predator, individuals in these colonies grow
defense spines.
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How animals learn
Learning from a single-stimulus
experience
 Sensitization and habituation
Pavlovian (Classical) conditioning (情淨
化：制約)
Instrumental (Operant) conditioning
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Numerous times each day a blue stick is placed in a rat’s
cage. If the rat takes less and less notice of the stick,
habituation has occurred. If the rat pays more attention to
the blue stick over time, sensitization has taken place.
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Ivan Pavlov and classical conditioning
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Terms
CS = conditioned stimulus
US = unconditioned stimulus
CR = conditioned response
Appetitive stimulus (正向刺激)
Aversive stimulus (負向刺激)
Excitatory conditioning
Inhibitory conditioning
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Cat odor
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Overshadowing and Blocking
Overshadowing–
 if the red light is always presented
simultaneously with the blue stick, just
prior to the presence of the cat odor (fig.
4.11), rats (group 2) will respond less
strongly to the blue stick.
Blocking –
 Rats first learned to associate the blue
stick and cat odor before any red light
was added. Then they are presented with
the stimulus to the red light. (Fig. 4.12)
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Operant conditioning, instrumental
conditioning, goal-directed learning.
 B. F. Skinner, Skinner boxes
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Why animals learn
Within-species studies
 Garcia’s rats (since the mid-1960)
• Cues, punishment, delay reinforcement
 Optimal forgetting
• in bees and stomatopods(口足目)
Population comparisons
 Group living in doves
 Antipredator behavior in sticklebacks
A model of the evolution of learning
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Imaging a bee
foraging at a
nectar-producing
flower. While it
might pay for the
bee to remember
the flower’s
location, it might
not be beneficial
to remember
specific nectar
content, as that
shifts within and
between days.
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Male and female
stomatopod
crustaceans share a
cavity for a few days
before they breed.
Although the males
leave the breeding
cavity soon after
mating, they tend to
remember their
former mates and to
be less aggressive
toward them during
the weeks that their
brood remains in the
cavity.
蝦蛄
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Population comparisons and the
evolution of learning
Learning, foraging, and group living in
doves.
 Animals in groups often find food faster
and have more time available for foraging
• Individuals who live in groups should learn
more quickly than territorial individuals.
• Zenaida doves (Fig.4.16 - 4.17)
Learning and antipredator behavior in
sticklebacks
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Learning and antipredator behavior
in sticklebacks
After a stickleback had learned that one
side of its tank was associated with food,
fish were subject to a simulated attack
from a heron predator.
 How long it took to learn to avoid the side
of the tank associated with heron predation
(and food) (Fig. 4.18)
 Fish from high-predation areas learned this
task more quickly than did fish from
predator-free populations.
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A model of the evolution of learning
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What animals learn?
Learning where home is located
 Juvenile salmon appear to learn the odors
associated with their natal streams, and
they subsequently use such information to
guide their way home. (pink salmon
migration, Fig. 4.19)
Learning about your mate
Learning about familial relationships
Learning about aggression
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Learning about your mate
 Mongolian gerbils are burrowing desert rodents
that rely on chemical communication during
many forms of social exchange, including the
formation of pair bonds.
 Differences between males and females in their
learning abilities should be positively correlated
with differences in male and female parental
investment.
 Mongolian gerbils and gourami fish, parental
investment is shared and learning differences
between the sexes are small.
 In Japanese quail, where there is no parental
investment on the part of males, males show
significantly greater learning abilities than do
females (Fig. 4.20)
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Learning about familial relationships
Young reproductively active long-tialed
tits breed independently as soon as
they can. (Fig. 4.21) However, most
nests fall victim to predation on the
young.
Breeders often become helpers at the
nests of their close genetic relatives,
and such helpers accrue indirect fitness
benefits by helping to raise their kin.
 How do the birds know who are kin?
 Play back experiment (Fig. 4.22)
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Individual birds
showed a strong
preference for the
calls given by their
close genetic kin,
staying for a longer
time near the
speakers that gave
off the calls of their
kin.
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Learning about aggression
Blue gouramis could be trained to
associate a light with either the
presence or absence of an intruder
male in their territory. (Fig. 4.23)
 Pavlovian learning
接受光訓練過的，打贏的機率較高，
 且接下來，繼續打贏的機率也較高。(Fig.
4.24)
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Molecular genetics and endocrinology of
learning
Molecular genetics of learning in rats
 More than forty years of breeding
• Syracuse High Avoidance (SHA) line
– Avoided shocks in forty of sixty trails (average)
• Syracuse Low Avoidance (SLA) line
– None of the sixty trails
 Gene differences
• Velil,SLC3al, Ptpro, and Ykt6p showed greater
expression in the hippocampus of SHA rats.
• SLC6A4/5HTT, Aldhla4, Id3a, and Cd74.
greater in SLA rats.
Endocrinology of learning in rats
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Endocrinology of learning in rats
Glucocorticoids (for example,
Corticosterone) are hormones that play
a large role in the stress responses and
learning of many animals.
 When pregnant female rats are stressed,
and glucocorticoid levels rise, the offspring
of such females show high levels of anxiety
and perform sub-optimally in learning tests.
 High-anxiety individuals took significantly
longer than low-anxiety animals to learn to
do so (water maze). (Fig. 4.25)
• High-anxiety animals had higher corticosterone
levels than did low-anxiety animals
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Phylogeny and the neurobiology of learning
 Phylogenetic work on learning is still in its
infancy.
 Innate versus learned behavior
 Learning has been documented in many
species of mollusks. In particular, snails in the
family Aplysiidae have become a model
system for studying the neurobiology of
learning,
 in large part because the nervous system of these
snails contains only about 20,000 large and
individually recognizable neurons that are grouped
into about ten clusters.
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Learning in snails
The sea hare, Aphysia californica, is the
best studied of the snail species in
which learning has been examined.
Serotonin appears to affect sensory
neurons in two ways: (1) serotonin
causes an increase in the duration of
the electrical signal that travels along
the axon, (2) serotonin increases the
number of action potentials that are
fired
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問題與討論
Ayo NUTN website:
http://myweb.nutn.edu.tw/~hycheng/