Stimuli and Communication Flashcards
What does communication involve?
Communication involves a transfer of information between animals.
What information is transferred?
The information may be about, the environment
*the signaller’s identity
*the signaller’s abilities
*the signaller’s future behaviour.
What does a signal reflect?
A signal reflects the state of the performer - the “message” (e.g. the animal is in reproductive condition or frightened) and has an effect on the recipient - the “meaning” (e.g. stimulates hormone production or initiates flight).
How is the information transferred?
information is transferred by signals that are specially evolved for communication, including sign stimuli
Sign stimuli
simple elements of a situation that elicit a behavioural response.
Give an example of sign stimuli
*Red breast of robin elicits aggressive response of rival
*Red patch on parent’s beak elicits pecking by herring gull chick.
*Swollen belly of female
stickleback elicits courtship
What did Tinbergan and Perdeck discover in relation to the red path on herring gull?
Using models, Tinbergen & Perdeck found that the gull’s head was unimportant, the presence of a contrasting spot on the parent’s mandible patch was effective, but red was a particularly effective stimulus
Supernormal stimuli
an artificial sign stimulus may evoke a stronger response than the normal e.g outsize egg better at stimulating incubation than normal egg
What is a sign stimulus selected from?
A sign stimulus is selected from a complex of stimuli both by the particular characteristics of the animal’s sense organs and by events in the central nervous system
Explain stimulus filtering by the sense organs.
Different animals have differing sensory capacities, and these make some stimuli more apparent than others for those animals.
Give an example of stimulus filtering by animals.
*Herring gull chicks: the gull’s retinal receptors have many droplets of red, orange and yellow oil, which would make red colours stand out from others.
*Tree frog male hears “co” and female hears “qui” of co-qui call due to differences in inner-ear neurons.
Explain Stimulus filtering by the CNS
Information about the environment reaching the central nervous system from the sense organs where it is subject to further “filtering”; many stimuli are perceived, but not responded to.
Which sensory modality used depends on…?
*the degree of development of the sense organs
*the distance over which the information is to be communicated
*the nature of the message
*the nature of the territory
Give an example of how characteristics of the signal may be adaptated to their function
bird alarm calls are of constant pitch and have a gradual start and finish, characteristics that make them hard to locate, while territorial calls are of varied frequency , making the caller easier to locate
Visual signals may be either…
Visual signals may be either structures (e.g. red patch on bill of gull) or behaviour patterns (e.g. pecking by chick at parents bill) or a combination of both (e.g. male fiddler crab waves specially modified claw).
