Term 2 Lecture 5: Communication

Question 1

Overlay of phylogeny and behaviour - phylogenetics

Answer 1

How behaviour can be constrained by phylogenetic history

Can help determine degree to which behaviour is influenced by phylogeny and evolutionary trajectories of behaviour

Question 2

How can we tell how behaviours evolved?

Answer 2

E.g. phylogenetic tree of canidae (Wayne et al 1989) can be omnivore/carnivore and solitary/ communal in care of offspring.
Clear patterns emerge such as the
N6 group are communal carnivores (grey wolf, coyote, cape hunting dog)
N1/3 show non communal care and omnivory (maned wolf, crab eating fox, racoon dog and grey fox)
N1 traits are the most ancient and n6 traits the most recently evolved.

Ask questions related to sequence and pattern of evolution of a behaviour

E.g. tool using in apes and crows shows convergent evolution

Although behaviour leaves little in terms of fossil records comparative studies can be carried out on related species.

Question 3

Homology Vs homoplasy (convergent evolution)

Answer 3

Phylogenetic analyses can verify suggested evolutionary pathways, they do not explain why behaviours have evolved the way they have

Question 4

Evolution of communication

Answer 4

Communication signals and displays serve specific functions. They did not appear ‘fully formed’ but evolved through history

Question 5

Evolution of a signal can depend on

Answer 5

-‘machinery’ available to the individual - physiology and morphology.
- evolutionary history of animals involved
- environment through which signalling is to occur
- the interests of signaller and receiver (don’t always coincide) - message Vs meaning eavesdropping etc.

Question 6

Evolution of signals can be influenced by receiver bias (machinery)

Answer 6

• which behaviours act as cues and become signals may depend upon sensory biases if the receiver
  If perpetual organs of the receiver have undergone selection for other functions e.g. insects that feed preferentially on yellow flowers use a mating display of bright yellow colouration - coopting existing system used for foraging

Question 7

Channel and life history

Answer 7

Channel selected for may depend on spp. Life history
Interspecific variation:
- harvester ants - feed on dead beetles if food is too big for one ant but can be managed by 2 the ant recruits using tactile communication
- fire ants - feed on large active prey requiring 7 workers they recruit using short term odour trails
- leaf cutter ants - feed on foliage or seeds - use long lasting odour trails

Question 8

Evolution of displays

Answer 8

General model of basic evolutionary process:

Sender (behavioural/physiological/morphological) cue
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E.g. on encountering an intruder in territory sender urinates)defecates for fight or flight response
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Receiver perceives cue - as territory marking perceives danger or challenge
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Receiver relates cue to motivation/ condition of sender - concludes it is risky to approach
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Decision rule - for own benefit
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Response - moves away from territory to avoid conflict
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If the response is beneficial this refines the cue to become a display (a ritualisation)
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Resulting in a ritualised display in this case with mutual benefit - warning territory boundaries
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Hence cue is repeated and reinforced as a behaviour

Question 9

What kind of behaviours did displays evolve from?

Answer 9

• intention movements - e.g. teeth baring as a threat shows intention - precursor of damaging behaviour
• displacement activities - occur in conflict situations when an animal is undecided as to the appropriate response to stimulus (as in territory marking)
• behaviour linked to physiological change e.g. threat display of fighting fish involves gill raising this is a ritualisation of the fishes natural response to widen gills to take in more O2 to increase metabolism in preparation for conflict
• thermoregulation behaviour e.g. displays involving hair raising
• elaboration of functional behaviours e.g. food exchange

Question 10

Elaboration of functional behaviours - examples

Answer 10

E.g. preening feathers in the courtship of birds - preening is necessary to maintain health of feathers and arrangement for flight but is also used in ritualised mating displays to show health and quality of the individual

E.g. food exchange : in pheasants and relatives a food call is used to alert other members of the flock to a food source (that’s the original/primitive behaviour) this has evolved so that females are attracted to the location of the displaying male even in the absence of food and the tail feathers are used by the male to make the display even more elaborate - seen in roosters, pheasants, imperial pheasants and peacocks

Question 11

Cost and benefits in context

Answer 11

-energy cost (developmental and performance)
- risk e.g. exposure to predation
- environment and ‘channel’
- eavesdropping costs

Question 12

Complex communication : honey bees

Answer 12

Not just in higher vertebrates
One of the earliest examples of complex communication can be seen in honey bees
Honeybees have a dance language (hypothesis Von Frisch 1967)
Honey bees perform movements on honeycomb to communicate where they’ve found food reserves outside the hive. Von Frisch placed food sources at various distances and angles from the hive and observed that when bees found them they returned to the hive to perform a waggle dance which other bees interpreted through tactile communication (as it’s dark within the hive)
If the food was within 200 metres then the bee would perform a round dance
If food was further away a waggle dance was performed in direction relative to the sun and direction of straight run related to gravity. The duration of the straight run increased with distance with one waggle every 30 metres

Question 13

Complex communication: Vervet monkeys

Answer 13

Different calls for different threats
eagle, leopard and snake.
But is it a simple stimulus response or do they understand the nature of the threat? It was hard to tell
So researchers tested it. Another local specie the superb starling also has an eagle warning call known as the ‘raptor alarm’ researchers played this call to the Vervet monkeys until they were habitualised to it and this habituation transferred to the monkeys own raptor alarm so that they no longer responded to other Vervet monkeys eagle alarm calls.
This suggests that they were able to translate their habituation to the starling call to their own species call so must have a generalized concept of an aerial predator.

Question 14

Language acquisition

Answer 14

-Most species have a limited repertoire of discrete signals even quite advanced mammals
- combining signals in different orders or modifying one by another
- language - humans are limited by 20-60 phonemes (distinct kinds of sound) that they can verbally produce
- humans combine these sounds in an infinite array of combinations, human language is therefore an unbounded signal set e.g. we can invent a word for every number from zero to infinity

• phonemes strung together into words/sentences - syntax
• many other species combine discrete signals in a way exactly like syntax

Question 15

So what is true language

Answer 15

Understanding of syntax - ability to produce and understand symbols conveying different messages depending on relative positions.

Use of symbols for abstract ideas

Displaced functional reference - referring to concepts, items, objects that are distant in both space and time - this may be a human only trait

Question 16

Research into great apes ability for language

Answer 16

Great apes:
E.g. chimpanzees (pan troglodytes)
-lack motor ability to produce human sounds
- can deal with other aspects of learning complex language

Chimps in language research:

Washoe (Gardner 1969,1989)
- learnt >100 words in American sign language from their handlers

Sarah(Premak 1971)
Was given plastic shapes in different colours and forms and was able to communicate by putting them together to make new worlds and phrases

Lana (Rumbaugh and Gill 1976)
Was given a computer designed for chimps, pressed buttons with symbols of hundreds of words combining them in new ways to achieve goals - nouns, verbs adverbs etc.

Conclusions from language studies of chimps (great apes) :
- chimps are able to combine words or symbols in novel ways to achieve different functional aims to obtain food, grooming etc.
- some argue that it is not proof of language to be able to combine discrete signals in a syntax way to achieve aims

• so can they use displaced functional references?

Sherman and Austin (Sauvage-Rumbaugh 1986)
- Sherman was given a container of food but needed a wrench to open it
- Sherman punches the appropriate symbol on his keyboard to signal to Austin in the adjacent room - a request
- Austin ‘knew’ a wrench was needed rather than another tool and handed it to Sherman through a flap in the wall
- Sherman opens the container and shared the food

^^^ proof of symbolic communication of displaced functional reference

Question 17

Counter research experiment against language use in apes

Answer 17

Epstein et al. (1980) named 2 pigeons Jack and Jill
They trained the pigeons to respond to an immediate stimulus to show that a complex sequence of behaviour can be generated to look like cooperation and coordination on the surface when infact it was just immediate stimulus response

Jack pecks a button in his room that asks ‘what colour?’ and Jill is shown a colour and Peck’s the relevant colour button informing jack of the colour.
Jack responds by pecking thankyou releasing food for Jill
The sequence is repeated for jack to get food.
“Demonstrated that pigeons can learn to engage in a sustained and neutral conversation without human intervention, one pigeon can transmit information to another entirely through the use of symbols” (sarcasm)

Question 18

Are any non human animals able to use communication akin to human language?

Answer 18

Alex the African grey parrot learnt via spoken English to identify more than 80 objects, quantity collections of up to 6 objects, identify shapes and colours.
He understood concepts such as “same” and “different”
^ is this using words to represent abstract concepts?