Handicap principle

The handicap principle proposes that costly signals are evolutionarily honest because only individuals of genuinely high quality can afford to produce them. A peacock's tail is not merely beautiful; it is a burden that only a healthy, parasite-free bird can sustain, making it a reliable signal of genetic fitness to potential mates. The principle transforms sexual selection from a runaway process of arbitrary preference into a system of costly signaling that maintains equilibrium through the very expense of the signal itself.

In social networks, the handicap principle explains why trust accumulates around visible sacrifice rather than cheap talk. The organism pays a cost precisely so that the signal cannot be faked.