托福口语 Task 4

Today we're going to talk about a fascinating concept in animal behavior known as 'sensory bias.' This is when a particular trait or behavior in one species evolves not because it directly helps survival, but because it appeals to the sensory preferences of another species, often a mate or a predator. Let me give you two examples. First, consider the guppy. Female guppies have an innate preference for bright orange spots on males. Interestingly, these orange spots are not linked to any health or strength advantage—they simply tap into the females' natural attraction to orange, which originally might have been a food color signal. Second, think about the bowerbird of Australia. Male bowerbirds build elaborate structures—bowers—decorated with blue objects like berries or bottle caps. Females are drawn to blue because it resembles the color of their favorite fruit. The males' display doesn't improve their physical fitness, but it exploits the females' existing color preference. So, in both cases, the trait evolves to satisfy a pre-existing sensory inclination.