In animal hierarchies, dominance must be communicated so that subordinates can defer and avoid costly conflict. Status signals solve this: visible displays of strength, health, resources that indicate rank without requiring constant fighting.1
In humans, status signals range from body language (posture, gait, eye contact patterns) to wealth displays (clothing, property, ornamentation) to behavioral signals (confidence, willingness to take risks).2
True status signals are costly—they're expensive to produce if you lack the underlying quality they signal. A healthy person can display flamboyant plumage; a sick person cannot afford the energy cost. A wealthy person can display luxury goods; a poor person cannot.3
Yet individuals have incentive to fake status—to display wealth they lack or confidence they don't feel. This creates selection pressure for detectors who can distinguish honest signals from dishonest mimicry.4
The evolutionary stable equilibrium maintains both honest and dishonest signals: some displays are too costly to fake (remaining reliable), while other displays are readily faked and thus provide no real information.5