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The Theory of Honest Signalling This is an old version of the
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Honest signalling in biology
Zahavi's handicap principle
Grafen's model
Attracting mates
Begging for food
Deterring predation
Contesting resources
Autumn color
Honest signalling in economics
Conspicuous consumption
Education
The mathematics of honest signalling
Signalling as a game
Other resources
Contact Information
Department of Zoology |
Honest signals in biology: From Zahavi's handicap principle... In the early 1970's, biologist Amotz Zahavi struggled to understand why animals often produce costly and extravagent displays or physical ornaments. Why to peacocks have such spectacular plumage? Why do baby birds beg so loudly? Why do gazelles jump up and down when they see a lion? To answer this question, Zahavi proposed that these extravagences are signals to other individuals. For example, a peacock's tail may be a signal used by prospective mates in order to estimate the individual's overall condition and/or genetic quality: "An individual with a well developed sexually selected character [such as a peacock's flashy tail] is an individual which has survived a test. A female which could discriminate between a male possessing a sexually selected character, from one without it, can discriminate between a male which has passed a test and one which has not been tested. Females which selected males with the most developed characters can be sure that they have selected from among the best genotypes of the male population. " (Zahavi 1975)Zahavi named his theory "the handicap principle," and suggested that there was something about costly behaviors or physical features that made for inherently reliable signals. But what is it about these costly traits - handicaps, as he called them - that makes them believable? This became a topic of great debate over the next fifteen years. [ Previous Page ] [ Next Page ]
Last modified September 4, 2002 |