2. Communication Flashcards
Why do animals communicate?
Very few organisms live in total isolation= Need some form of directed signal
Have interactions with hetero-specifcs (different species)
Have interactions with conspecifics (same species)
At the very least, communication is needed for reproduction
Also have aggregations and non-random associations among individuals
Social interactions: E.g. for defending territories and choosing a mate
What are the components of a communication system?
Directed signal (Sender)
With response of recipients (reactor)
What is communication?
What are displays?
An action on the part of one organism (or cell) that alters the probability pattern of behaviour in another organism (or cell) in a fashion adaptive to either one or both of the participants
Sender must INTEND to alter another’s behaviour
OR: Communication is a means by which the sender manipulates the receiver, who may benefit or may be harmed
Displays: Behaviour patterns specially adapted to serve as social signals
What is true communication?
When both the sender and receiver gains from the information
Purpose of display is not so much to inform as to persuade
What are the types of signals?
1) Discrete signals- All or none, on or off Example: agressive or not Zebras: Hostility= Flattened ears Friendliness= Raised ears
2) Graded signals: Intensity varies in proportion to stimulus strength e.g. how aggressive are they
What is the difference between referential and afferential signals?
Referential: Communicate information about an entity that is external to the communicating individuals e.g. alarm calling when there is danger to warn others
Afferential: Communicate some information about the sender itself e.g. could send a message that they are aggressive
What are the different ways of increasing signal information?
Composite signal: 2 or signals combined with meaning
Syntax: Changing the sequence of displays
What is the importance of context?
Same signal can have different meaning depending on context e.g. what other stimuli are received
Example: Lion’s roar can mean:
-Spacing device for neighbouring prides
-Aggressive display in fights between males
-Maintaining contact among pride members
What is metacommunication?
Communication about communication- Communication that alters the meaning of the message that is to follow
One display changes meaning of those that follow
Example: Play behaviour where the play behaviour is initiated first and the aggressive, sexual displays follows are all play
What is the difference between message and meaning?
Message: What the signal encodes about the sender e.g. what it is, what its up to and what it might do next
Meaning: What the receiver interprets from the signal
Often meaning and message could mean the same thing if both know what the message was meant to mean
Example: Male bird singing in its territory as the same message could have different meanings for different receivers
What is the cost and benefit of signalling, using examples?
Benefits: Signalling could be less costly way of manipulating behaviour of another individual other than using physical force as it reduces the chances of injuries and therefore less energy is wasted
Example: Male cricket
Cost: Could lead to exhaustion
Example: Red deer stag roaring contests could be exhausting
Other individuals could be eavesdropping= Unintended receiver picks up the message
What can signallers do to reduce the risk of eavesdropping?
1) Have signals difficult for eavesdroppers to detect or locate e.g. sound frequencies can be evolved to be difficult to locate
2) Have signals which are selectively unavailable to predators e.g. Red spots: Infraspecific signal in poeciliid fish as invertebrate predators are red-blind
3) Have direct signals to specific individuals
Example: Squids can change the colour of their skin e.g. can either be on the left side or right side so that the other side is camouflage
What are the different things which evolution of communication can depend?
1) Machinery available to the individual
2) Evolutionary history of the animals involved
3) The environment through which signalling is to occur
4) The interests of signaller and receiver
5) Receiver- bias: The machinery available to the receiver as which behaviour acts as cues and become signals may depend upon sensory basis of the receiver
Example: Insect feeds preferentially on yellow flowers- Bright yellow patches are used in mating displays
How can sound degradation interfere with signalling?
Degraded signals may be confused with other signals or sounds, or simply ignored
Worst for high-frequency sounds
Echoes can interfere with rapidly repeated signal elements
What are some strategies to reduce degradation?
In forests: Low frequency and avoid trills unless notes widely spaced
In open terrain: Trills favoured, repeated elements can be detected during brief periods of good transmission
