Signals
Signals are acts or structures produced by a sender that alter the behavior of a receiver. These acts or structures have evolved specifically because of their effect on the receiver, and their effectiveness relies on the receiver’s evolved response. This distinguishes signals from cues, which are simply features of the world that can be used as a guide to future action but haven’t necessarily evolved for that purpose.
There are several types of signals, including visual, auditory, chemical, and tactile signals.
the songs of birds are auditory signals which attract mates and defend territories
Signals have been shaped by natural selection and their function is closely related to the information they convey. For a signal to be effective, it must benefit both the sender and the receiver, at least on average.
There are several factors which contribute to signal honesty.
Signals are inherently reliable because they’re directly linked to an animal’s anatomy or physiology and cannot be faked.
These signals are costly to produce and the cost is greater for lower-quality individuals. Only high-quality individuals can afford the expense of producing these signals, making them honest indicators of quality.
the classic example is the peacock’s tail: only the fittest males can afford to grow and maintain such elaborate plumage.
When the sender and receiver share a common interest, there’s no incentive to deceive. This is often the case in kin selection, where individuals benefit by helping their relatives.
for example, the waggle dance of honeybees is an honest signal because the workers share a common interest in finding food
Dishonest signals can incur social costs, such as punishment or loss of reputation. In systems where individuals interact repeatedly and remember past encounters, dishonest signalers can develop a bad reputation. Receivers may learn to ignore signals from individuals known to be unreliable.
Dishonest signals do exist, but for a signaling system to remain evolutionary stable, there must be a balance between honesty and dishonesty. Dishonest signals can persist if they are relatively rare so that, on average, it still pays the receiver to respond to the signal.
They can also persist if they exploit pre-existing adaptive responses in the receiver.
for example, a Batesian mimic benefits because its resemblance to a dangerous species triggers an evolved avoidance response in the predator.
The existence of dishonest signals highlights the ongoing evolutionary arms race between sender and receivers. Senders are constantly seeking ways to manipulate receivers to their advantage, while receivers are evolving ways to discriminate between honest and dishonest signals.