The handicap principle is a disputed hypothesis proposed by the Israeli biologist Amotz Zahavi in 1975. It is meant to explain how "signal selection" during mate choice may lead to "honest" or reliable signalling between male and female animals which have an obvious motivation to bluff or deceive each other. The handicap principle suggests that secondary sexual characteristics are costly signals which must be reliable, as they cost the signaller resources that individuals with less of a particular trait could not afford. The handicap principle further proposes that animals of greater biological fitness signal this through handicapping behaviour, or morphology that effectively lowers overall fitness. The central idea is that sexually selected traits function like conspicuous consumption, signalling the ability to afford to squander a resource. Receivers then know that the signal indicates quality, because inferior-quality signallers are unable to produce such wastefully extravagant signals.
The peacock tail in flight, a classic example of what Amotz Zahavi proposed was a handicapped signal of male quality
Luxury cars and other "Veblen goods" may be an example of the handicap principle in humans
Impala stotting, a behavior that may serve as a pursuit deterrence signal to predators
Amotz Zahavi was an Israeli evolutionary biologist, a Professor in the Department of Zoology at Tel Aviv University, and one of the founders of the Society for the Protection of Nature in Israel. His main work concerned the evolution of signals, particularly those signals that are indicative of fitness, and their selection for "honesty".
Amotz Zahavi in 2005
Zahavi with wild Arabian babblers, whose social behavior he studied
