Download Lecture 26 - The University of Texas at Dallas

12/7/2015
PSY 2364
Animal Communication
Homework assignment #2
Comparison of animal communication and human language
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Due date: Wed. Dec. 9
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List and describe a set of universal properties
that are found in language.
(a) To what extent are these properties unique to
language? (b) To what extent are they also found
in animal communication systems? Give
examples where appropriate.
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Prosimians
 Ceboid (New World) monkeys – C. & S. America
Apes
 Lemurs – Madagascar
 Lorises, galagos and their allies – Africa, Asia
 Tarsiers (tarsiers, tree shrews) – Philippines, S.E. Asia
Monkeys
Order: Primates
 Cercopithecoid (Old World) monkeys – guenons,
mangabeys, macaques, baboons, langurs, etc.
 Lesser Apes (Hylobatidae) – gibbons and siamangs
 Great Apes (Pongidae) – chimpanzees, bonobos,
gorillas, orangutans
Approximately 2 double-spaced, typed pages
Submit by via eLearning
Primate evolution
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Primates are intelligent animals.
What factors are linked to higher intelligence?
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4.
Arboreal living
Sociality
Fine motor skills
Diurnal life style
 Humans (Hominidae)
Primate evolution
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Brain-body size
Primates are intelligent animals.
What factors are linked to higher intelligence?
5. Generalized adaptation to greater environmental
complexity
6. Large size
7. Large brains
8. Longevity
The brain of a horse (Equus caballus) is more than six times
bigger than that of a rhesus monkey (Macaca mulatta). But if
they were equated for body size, the monkey would have a
20x larger brain.
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Brain-body size
Diet and brain size
• Within the primates, species that eat fruit tend to have
relatively larger brains than species that mainly eat
leaves.
Spider monkey
Fruit diet
Neocortex
• The neocortex is the layered outer shell of
the brain, and is found only in mammals.
• Primates show expansion of the neocortex.
• In humans 80% of the brain is taken up by
neocortex, compared to less than 20% in
shrews.
Howler monkey
Leaf diet
Neocortex
• Convolutions (wrinkles) in the primate
neocortex provides increased surface area.
Cortical plasticity
Most primates are social animals
• An important property of the neocortex is
plasticity. This term refers to changes that take
place in the neocortex when connections are
formed or strengthened along frequently used
neural pathways, or when unused connections are
weakened or lost. During the lengthy period of
juvenile development, the wiring of the primate
neocortex is modified through learning and
interaction with the environment.
• Most species of primates live in social groups
consisting of both males and females and young.
• Members of the group may spend their entire life
with the same individuals, and get to know each
other well.
• The context of a communication signal includes a
network of social relations that have a long
history. This history helps determine how a signal
is interpreted and responded to.
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Social learning
• Observation-based learning
• Food sharing
– White-faced Capuchin monkeys
– Chimpanzees: termite fishing
– see Dugatkin p. 174-175
Social Learning
• Copying
Social learning
• Learning by imitation
– Developing a behavior as a result of observing
another individual performing that behavior
– Manipulation of objects to reach a desired
outcome (e.g. potato washing in macaques)
– Strategy for reaching a goal may be specific
(budgerigars adopt different strategies to
uncover food (beak vs. foot) depending on what
the model did; Galef, 1986)
Social Learning
• Teaching (pedagogy)
– Observer repeats the behavior of another
individual
– Sometime accompanied by rewards
– Differs from imitation in that the action does
not need to be novel, nor does it necessarily
involve a topographically novel response.
Vocal learning
• How much of primate communication is the
result of learning?
(1) producing the appropriate call (acoustic structure);
– One individual serves as the instructor, the
other as the student who learns from the teacher
– Implies an immediate benefit for the student but
not for the teacher
– Examples: hunting in cheetahs
Vocal learning
• Production of calls is largely independent of
experience and learning (but studies are
limited).
(2) using the call in the appropriate social context;
(3) understanding the significance or responding to the
call in the appropriate manner.
–Winter et al. (1973) found that
infant squirrel monkeys
developed normal vocalizations
even if they were deafened when
4 days old, or when raised in
isolation.
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Old World monkeys
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Call classification by vervet monkeys
• Vervet monkeys give acoustically distinct
calls for different predators, and result in
different behavioral responses:
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Primates
Family: Cercopithecidae
Genus: Chlorocebus
Species: aethiops
– Leopards (run and climb into trees)
– Eagles (look up, run into bushes)
– Snakes (mobbing response)
Vervet monkey
Vocal learning
• Perception of calls may be shaped by learning.
– Infant vervet monkeys do not produce any alarm
calls before the age of 1 month, and only rarely at 6
months.
– Infant vervet monkeys often produce alarm calls in
the wrong setting, but they improve with age
(learning by imitation).
Vocal learning
• Cheney and Seyfarth (1996): Vervet monkeys
appear to interpret the calls as sounds that
represent objects and events in the external
world.
• If a vervet monkey is habituated to the leopard
alarm call (by playing it repeatedly without a
leopard in the vicinity) the animal stops
responding .
• Playback experiments (Cheney & Seyfarth,
1988) elicit the same responses, even when
the predator is absent
Vocal learning
• Perception of calls may be shaped by learning.
– Vervets younger than 3-4 months run to their
mothers when they hear alarm calls. After hearing
an alarm call they often look at their mother. By 6-7
months they respond in the same way as adults.
– Vervets also respond to alarm calls given by birds,
such as the Superb Starling. This is probably a
learned behavior.
Vocal learning
• A recording of the eagle alarm call produced by
the same individual does not produce any
response either.
• But a recording of the eagle alarm call produced
by a different individual produces the expected
response (hiding in bushes).
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Evidence for vocal learning
• How much of primate communication is the
result of learning and imitation?
(1) producing the appropriate call (acoustic structure);
(2) using the call in the appropriate social context;
(3) understanding the significance or responding to the
call in the appropriate manner.
• Production of calls largely independent of
experience and learning (but studies are limited)
Primate life styles
• Most primates are arboreal (forest, jungle).
• Some old world monkeys (e.g. olive
baboons) are terrestrial, i.e. adapted to
living and foraging on the ground.
• Some apes (gorillas, chimpanzees) spend a
lot of time on the ground.
• No primates are exclusively terrestrial.
• What about perception?
Primates – physical traits
• Features shared with other mammals
– e.g., giving birth to live young, fed on milk
• Features that define primates as unique
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tendency toward erect posture
prehensile (grasping) limbs
5 digits on hands and feet
opposable thumb; fingernails rather than claws
long gestation period, delayed maturation, long lifespan
Primates – diet
• Most primates are omnivorous and eat a
combination of fruits, seeds, leaves, and
insects
• Some species kill and eat small mammals
• Some eat mainly leaves
Primates – sensory systems
Primate communication systems
• Binocular vision: eyes positioned in the
front of the face provides capacity for depth
perception and stereoscopic vision.
• Color vision: Diurnal primates see in color;
nocturnal primates lack color vision.
• Acute hearing
• Reduced reliance on olfaction
• Expanded brain size (cerebral hemispheres)
• Primate communication is multimodal
(vocalizations, facial expressions, gestures,
postures, tactile contact signals, olfactory
signals).
• Primate communication takes place within
an extended context, not in isolation
– same sound may appear in different situations
– context helps to determine meaning (response)
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Marler (1965)
• Multimodal signals
• Long-term social contacts
• Short-range signals
– calls, visual gestures and postures, contact
• Long-distance signals
– usually unimodal, because of signal degradation
– specialized structures for long-distance vocalization
(throat pouches used for long calls by howler monkeys
and siamangs)
Variety of message states
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Submissiveness
Aggression
Anxiety
Fear
Mating and courtship signals
Parent-infant interactions
Culture in chimpanzees?
• Whiten, Goodall, McGrew, Nishida, Reynolds, Sugiyama,
Tutin, Wrangham and Boesch (1999). Culture in
chimpanzees. Science 399: 682-685.
• Field studies from 7 long-term studies revealed patterns of
variation far more extensive than previously recorded for
any animal species except humans.
• 39 different behavior patterns including tool usage,
grooming and courtship behaviors consistent with the idea
of cultural transmission.
Marler (1965)
• Discrete versus graded signals – many primate
signals are graded; variations in meaning are
correlated with small changes in behavioral pattern
rather than discrete and different behaviors.
• Graded signals are well suited for conveying
messages along a continuous scale (e.g. degree of
confidence or aggression level).
• Discrete signals are well suited for delivering a
single message (e.g. vervet monkey alarm calls)
Variety of message states
• Signals to coordinate group movements, dispersal
– increase distance (territorial exclusion)
– maintain distance (constant spacing of adjacent troops)
– reduce distance (bring animals together)
• Environmental information
– So far, restricted to alarm calls for different types of
predator
Cultural Transmission
• Transfer and acquisition of information via
social learning and teaching
• Learned patterns are passed on from one
individual to another
• Cultural transmission involves a “model”
and an “observer” who learns a specific
behavior from the model
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Cultural Transmission
• Vertical transmission: information is
passed from parent to offspring
– Some songbirds learn the species-specific song
by listening to their father sing
– “Sponging” behavior in dolphins: learned
behavior in female bottlenose dolphins, who
break off a piece of marine sponge to protect
their mouths when probing the sea floor for fish
prey
Cultural Transmission
• Horizontal transmission: information is
transmitted from peer to peer
– Guppies form foraging groups with peers of
similar age and size
– Laland &Williams (1998) trained 2 groups of
guppies. One group trained to follow a short
path to a food source, the other a long path.
When new members were added to each group,
they adopted the learned strategy of the group.
Cultural Transmission
Snake aversion in monkeys
• Oblique transmission: information is
transmitted across generations but not from
parent to offspring
• Lab-raised monkeys who have never seen a
snake do not respond in the same way as
wild-raised primates who have seen them.
• Observing an adult model respond to snakes
with fear gestures and actions, a juvenile
rhesus monkey adopts the same gestures.
• This happened even when the model was
not related to the juvenile (oblique
transmission)
– Common in species with no parental care
– Predator recognition in blackbirds
– Snake aversion in rhesus monkeys
Snake aversion in monkeys
• In one condition juveniles observed an adult
monkey who had been conditioned to show
a fear response in the presence of a neutral
object (flowers). But in this situation the
juvenile did not display fear when exposed
to flowers, suggesting an interaction of
oblique transmission with an innate
predisposition to fear snakes.
Local enhancement
• Not all interactions between individuals
involve cultural transmission.
– Local enhancement describes situations where
one individual is attracted to an area because of
the actions of another individual (or group of
individuals) that are already there. Learning is
not the result of observing another’s behavior.
– Example: Cliff Swallows find good foraging
areas by looking for crowds of swallows.
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Social facilitation
• Not all interactions between individuals
involve cultural transmission
– Social facilitation describes situations where
the mere presence of an individual in an area
facilitates learning on the part of another
animal.
– Example: increased group size leads to
increased foraging rates in Starlings.
Cultural transmission
• Interaction of cultural transmission and
genetic inheritance
• Learning and transmission of bird song in
Galapagos finches
– Learned behaviors may serve as reproductive
isolating mechanism
– Females selectively mate with males who sing
the species-specific song
Foraging behavior
• Experiments on the use of a novel food
source by Capuchin monkeys (Cebus
paella). The novel food source was sampled
by a lone monkey only when it was in view
of other monkeys eating a different type of
food; not when the other monkeys were
present but not eating anything (supports
local enhancement, not social facilitation).
Cultural transmission and brain size
• Studies of primate brain anatomy indicate a
significant positive correlation between
brain size and the frequency of tool use,
social learning and innovation.
• In this study, brain size was a better
predictor than brain-body ratio.
Hockett’s design features of language
What is language?
Bee dance Bird song Language
Vocal-auditory channel
• Hockett’s design features of language:
• All human languages share 16 basic properties
that distinguish language from other forms of
communication in animals.
• Some (but not all) of these properties may also
be found in animal communication systems.
Rapid fading
Charles Hockett (1966). The Problem of Universals in Language.
Interchangeability
Total feedback
Specialization
No
Yes
Yes
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Yes
Yes
Some
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Yes
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Yes
Yes
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Yes
Yes
Semanticity
Yes
Yes?
Yes
Arbitrariness
No
Yes?
Yes
Discreteness
No
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Yes
Displacement
Yes
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Yes
Productivity
Yes
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Yes
Traditional transmission
No
Yes
Yes
Duality of patterning
No
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Yes
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Levels of linguistic analysis
Phonetics
1. Phonetics – speech sound production/perception
2. Phonology –patterning of sounds (phonemes) in a
language
• Speech sound
production
• Speech sound
perception
3. Morphology – principles of word (morpheme)
formation
4. Syntax – organization and arrangement of
morphemes in sentences
5. Semantics – study of meaning
6. Pragmatics – language use in social context
Phonology
• Phonology is the study of sound patterning
in a given language
• Phonemes are the sound units in a given
language
Phonology
• Phonemes
– Small units of language; do not convey
meaning by themselves
– Minimal pairs test (“pit” vs. “bit”)
– American English has 12 vowels (e, o, u, …)
and 24 consonants (p, t, k, …)
Morphology
Syntax
• Morphology is the study of word construction
in a given language
• Morphemes are the smallest units in a
language that carry meaning
• Syntax is the study of the principles and rules
for constructing sentences in a language.
• Units of syntax are the traditional “parts of
speech” (nouns, verbs, adjectives, adverbs)
• Syntactic theories describe the rules of
sentence construction (rules of grammar)
– Morphemes are similar to words, but some words
consist of more than one morpheme
– dogs = ‘dog’ + ‘s’ (plural marker)
– Formal mathematical theories
– Characterization of grammatical knowledge
(Chomsky)
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Semantics
• Semantics is the study of meaning
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Lexicon (dictionary)
Color terms
Kinship terms
Cross-language comparisons
Language acquisition
• Critical period for language acquisition?
• Hemispheric specialization
• Recovery from aphasia
• Stages of language development
• “Motherese” (infant-directed speech)
• Prosody of speech
Milestones of speech development
(P. Kuhl, Nature Neuroscience Reviews, Nov 2004)
Infant-directed Speech
• Limited vocabulary, concrete reference
– doggie, potty, choo-choo train, boo-boo
• Simple syntax: short sentences; more
imperatives and questions
• Precise articulation
• Repetition
• Exaggerated pitch contours
– “what a good boy!”
Infant-directed Speech
Prosody – melody of speech
1. approval heavily modulated, extensive
rise/fall in fundamental frequency (pitch)
2. prohibition ("NO!")
3. attention (shorter than approval, more
rapid rise to maximum)
4. comfort (relatively unmodulated,
downsweep in fundamental frequency)
Infantdirected
speech
P.K. Kuhl (2004).
Early language acquisition:
Cracking the speech code.
Nature reviews – Neuroscience
Volume 5 | Nov 2004 | 831
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Learned communication
Language and animal communication
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Vocal imitation and invention
Vocal tract anatomy and motor control
Perceptual abilities
Brain mechanisms
Theory of mind, attribution of mental states
Referential signaling
Rule-based learning, sign language,
artificial language systems
• Factors that favor learned communication:
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Learned communication
Sources of evidence for learning
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existence of (learned) dialects
interspecific mimicry
acoustic isolation
deafening to remove auditory feedback
disruption of neural pathways (CNS lesioning)
tape tutoring (birds); social tutoring (captive
rearing)
• cross-fostering (young reared by adults of another
species)
Learning and behavior
Variability in signal production & perception
Individual or group recognition
Adaptation to unpredictable environments
Need for complex decision making
Long period of parental care
Stable long-term social interactions
Capacity for imitation and invention
• Factors that favor learned communication:
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Variability in signal production & perception
Individual or group recognition
Adaptation to unpredictable environments
Need for complex decision making
Long period of parental care
Stable long-term social interactions
Capacity for imitation and invention
Tool use and learning in crows
• Captive New Caledonian crows have
learned to develop and use tools to solve
complex problems.
• This crow was able to bend a piece of
straight wire into a hook, and used the
hook to lift a bucket containing food
from a vertical pipe.
• Reference: Weir, Chappell, & Kacelnik
Science 297, 981 (2002).
• http://www.youtube.com/watch?v=fumsiIGE9c0
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Mirror self-recognition
Joshua M. Plotnik, Frans B. M. de Waal and Diana
Reiss (2006). Self-recognition in an Asian
elephant. PNAS 103 (45): 17053–17057.
Mirror self-recognition
• Previously found only in humans, apes, and
dolphins
• MSR involves four stages:
(i) social response
(ii) inspection (e.g., looking behind the mirror)
(iii) repetitive mirror-testing
(iv) self-directed behavior (i.e., recognition of
the mirror image as self)
www.pnas.orgcgidoi10.1073pnas.0608062103
Word learning by a dog
Word Learning in a Domestic
Dog: Evidence for “Fast Mapping”.
Juliane Kaminski, Josep Call, Julia Fischer
Science 304: 1682-1683.
www.sciencemag.org/cgi/content/full/304/5677/1682/
A border collie, Rico, learned the labels of over 200
different items. He inferred the names of novel
items by exclusion learning and correctly retrieved
those items right away as well as 4 weeks after the
initial exposure.
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