托福口语 Task 4

Today we're going to talk about a fascinating concept in animal behavior called 'sensory bias.' This is when an animal's pre-existing sensory preferences—like a liking for certain colors or sounds—influence how they evolve, particularly in terms of mate selection. The idea is that these preferences didn't originally evolve for mating purposes, but they end up being exploited by potential mates. Let me give you two examples. First, consider the guppy. Female guppies naturally are attracted to orange colors, possibly because in their environment, orange signals food, like ripe fruit falling into the water. Males with brighter orange spots are more likely to be chosen by females, even though the orange spots don't directly indicate health or fitness. Second, think about the bowerbird. Male bowerbirds build elaborate structures, or bowers, and decorate them with blue objects—berries, feathers, even plastic. Females are drawn to blue, perhaps because blue is a rare and striking color in their forest environment, or maybe because it mimics the color of certain edible flowers. The males who collect the most vivid blue items get more female visits and mating success. In both cases, the preference existed before the trait, and the males evolved to exploit that preference.