Biology of Business

Biological signals as handicaps

Alan Grafen

Journal of Theoretical Biology (1990)

TL;DR

Mathematical proof that costly signals remain honest because cheating becomes prohibitively expensive for low-quality signalers.

By Alex Denne

Provides the mathematical formalization of Zahavi's handicap principle, demonstrating rigorously that costly signals can be evolutionarily stable honest communication systems. Essential for understanding the game-theoretic foundations of signaling.

Key Findings from Grafen (1990)

  • First rigorous mathematical proof that handicap signaling is evolutionarily stable
  • Honest signaling requires differential costs—signal must be relatively cheaper for high-quality signalers
  • Equilibrium conditions parallel Spence's 1973 job market signaling model exactly
  • Cost-quality correlation necessary: peacock with better genes bears lower marginal cost for same display
  • Dishonesty fails not because impossible but because prohibitively expensive for low-quality cheaters
  • Published in Journal of Theoretical Biology, volume 144, pages 517-546

Related Mechanisms for Biological signals as handicaps

Related Organisms for Biological signals as handicaps