Fisherian Runaway Selection
A feedback between inherited preference and trait can amplify sexual ornamentation.
The Mechanism: Fisherian runaway selection proposes that a heritable preference and a heritable trait can become correlated, amplifying each other across generations. The process depends on genetic variation, mate choice, and tradeoffs with survival.
The Philosophical Pivot: A trait's prominence does not prove that it is useful in every way. Selection can favor a costly signal when reproductive advantage offsets some costs in a particular environment.
The Horizon: The model explains one possible path for elaborate traits, not every ornament or preference. Real mating systems involve ecology, competition, mutual choice, and multiple selection pressures.
The language of runaway can make change sound inevitable, but environmental conditions and costs can alter its direction or halt it.
What looks like excess from one perspective may reflect a history of choices made across many generations.
A trait can grow more elaborate through preference without becoming more useful in every sense.
Which standards of attractiveness do I treat as natural when they may be shaped by feedback and history?