Sexual selection provides an answer to the existence of lavishly ornate signals in animals, but not to the question of why such signals are attractive—for example, why do females prefer the extravagant plumage of peacocks? As part of an international team, researchers at Eötvös Loránd University (ELTE) have shown that the reason is not the presumed wasteful cost of ornaments, as honest signals need not have to be costly at all as long as cheaters would have to pay to fake them.