Decoy effect (asymmetric dominance)

Biological Parallel

Female guppies exhibit mate-choice copying: when a less attractive male is positioned near a highly attractive one, the attractive male becomes even more desirable by comparison. This asymmetric dominance effect—where adding an inferior option enhances a superior neighbor—is widespread in animal mate choice. The "decoy" male makes the target's quality more salient through direct comparison, demonstrating how choice architecture shapes preference in ways unrelated to absolute quality.