Communication
&
Cognition
How do primates share information?
What kinds of information do they share?
What does this tell us about their mental
abilities?
4 components of communication
• Signal
• Motivation
• Meaning
• Function
1. Signal
•
•
•
•
•
observable action
may be recordable depending on mode
simple or complex
often used together and in rapid
succession to convey clear, unambiguous
messages e.g. aggression
Signal maybe innate, but appropriate use
must be learned in a social context.
e.g. Texas rehab macaques
Open mouth gape (double threat)
Male branch display
2 brothers display in parallel
(photo credit: B. Gray)
2. Motivation
•
Internal state of the animal (feelings,
emotions, intentions).
•
Usually inferred from the actions that
accompany the signal.
3. Meaning
•
Determined by the reaction of the
receiver(s)
•
Inferred from the context of situation
4. Function
•
Adaptive value of the signal to either
the sender or the receiver.
e.g. alarm calls
threats
courtship gestures
SIGNAL---------------------------REACTION
(short bark)
(group runs & looks up)
environmental context: hawk flying overhead
MOTIVATION of sender: fear, startled
MEANING to recipients: take cover, watch sky
FUNCTION: warns others to be careful!
Observations and Inferences
Observations:
Signal
reaction
context
Inferences:
Motivation
environmental
meaning
function
4 Modes Of Communication:
•
•
•
•
Olfactory
Visual
Tactile
Auditory/Vocal
Olfactory Communication
• Oldest form of communication
• Uses chemical signals
• Conveys message after the sender
has left
Scent
marking
• Dispersed in the air
• Deposited on
substrates
Functions:
 Mark territories
 Attract mates
 Advertise dominance
status
 Sexual receptivity
 Aggressive/competitive
encounters
Olfactory communication most important in
solitary, nocturnal primates e.g. lorises, galagos
Visual Communication
• Most commonly studied because it is
the easiest
• Most ethograms and recording devices
focus on visual signals
• Four main types: facial expressions,
body postures, tail postures, coloration
• Facial expressions
Permit very diverse messages
Good for close range messages
Many are universal (stare, grimace)
More limited in prosimians
Patas monkey male plays with a juvenile, Erythrocebus patas
(photo credit: A. Wolfe)
• Body and tail postures
better for distance messages
Courtship; dominance
Coloration - silverback
Coloration - bright
colors face and body
Coloration - natal coat
(especially colobines)
Vocal Communication
• Becoming one of the main research
areas in non-human primates
Sonogram/graph:
Provides a spectographic picture of the
sound waves
• Primates display great variation in vocal
pitch and intensity
Vocal Communication
• Ability to attract the receiver(s) attention
without being in view.
• Some arboreal have developed
anatomic specializations to call long
distance through the forest.
e.g. howler monkeys, siamangs
Cheney and Seyfarth
Playback experiments on wild vervets revealed
that vervets (a cercopithecine)
•
•
•
•
Identify individuals by their vocalization
Recognize relationships
3 Alarm calls – snake, leopard, raptor
4 Contact calls – dominate, subordinate,
non-group member, individuals in an
open area
Tactile Communication
• Difficult to study since we can’t perceive
the message the same as the receiver.
• Occurs in intense and intimate social
interactions.
e.g. mother/infant; female/male consortship
Grooming
• The most studied form
of tactile
communication.
• Primary function is to
maintain social bonds
and reduce tension.
• Secondary function is
to remove parasites
Observed in many different social
contexts:
•
•
•
•
Mothers pacify infants
Prelude to mating consort pairs
Reinforces kinship bonds
Reduces tension between potential
adversaries
• Involved in reconciliation
Self grooming:
• Personal hygiene
• Appears to calm individuals in tense
situations.
Other tactile behaviors:
• Greeting and reunion hugs and kisses
e.g. chimpanzees and spider monkeys
Communication systems are needed for
• the complex social lives of primates
• sharing of ecological information
Communication is a window into the
cognitive abilities or intelligence of
primates
Intelligence is notoriously
difficult to define
Large brain relative to body size?
Flexible problem solving ability?
Convoluted brain?
Complex behaviour?
Mental representations?
Thoughts?
Consciousness?
Others?
Intelligence:
A single unitary capacity
(Domain general)
or
Many different capacities
(Domain specific)
What are primate big
brains for???
Finding food?
Dealing
with
others?
What selection pressure favored
intelligence in primates?
2 main possibilities
1. Ecological factors associated with
locating and processing inaccessible
food items
2. Social factors associated with life in
large complex social groups
Ecological Intelligence – selection
would favor:
• Ability to form spacial mental map of food trees
• Ability to predict temporal variation in seasonal
foods (form temporal maps?)
• Ability to extract difficult to find or eat foods (ex.
hard shelled nuts, buried roots and tubers, insect
larvae hidden in tree bark, seeds contained within
pods
• Ability to use tools to access food
Chimpanzee, Pan troglodytes (photo credit: S. Robinson)
Chimpanzee, Pan troglodytes
West Africa, ‘Stone Hammer’
Chimpanzee, Pan troglodytes
West Africa, ‘Stone Anvil’
(photo credits: C. Bromhall)
Evidence that intelligence
in primates is linked to diet?
Cebus monkeys
• highly extractive foragers
• considered the most intelligent NWM
Spider monkeys (frugivores) have twice
the brain size of howlers (folivores) close relatives, same forests
Social Intelligence – selection
would favor:
Ability to
• deal with conflict and competition
• form coalitions and alliances
• form dominance hierarchies
• reconcile disputes (make peace)
• deceive others, detect deception
• form enduring social bonds
• engage in reciprocity
• keep track of own and other’s relationship
Evidence that intelligence in primates
is linked to social complexity?
Dunbar Social Brain Hypothesis (& Study)
Compiled data from 25 primate species on
• Size of neocortex (relative to rest of brain)
• Diet (folivory vs frugivory and extractive foraging)
• Group size
Found that
• Group size is positively correlated with larger
neocortex
• No correlation between diet and neocortex size
Deception
Deception – behavior that acts to
persuade another to believe something
that is false
Animal Examples
• quail feign injury to lure predators away
from young
• Insects mimic the appearance of foul
tasting species to trick predators
• Camouflage – lots of animals
Deception in primates
Involves
1. flexible behavior patterns
and
2. interactions between and among
members of the same species
Examples – fake trauma, fake alarm calls,
hiding to mate, pretending not to see
food
Theory of mind
Deceptive behavior in primates suggests
that some species possess the ability to
think about what another individual is
thinking
Can primates distinguish between what
they know and what another animal
knows?
Can they attribute thoughts and motives
to others?
Do most primates have a “theory of
mind”?
Adult humans - yes
Small children – no
• cannot necessarily distinguish what they
know from what others know
• Example - Smarties in a matchbox test
Other primates?
Probably not, but maybe adult apes
Limits to Primate Intelligence Transferability
Capacity in one domain is not necessarily
transferred to another
Ex – vervets & python tracks/stored
carcasses