TOEFL Speaking Task 3

The concept of 'signaling theory' in biology suggests that certain traits or behaviors in animals serve as honest signals of an individual's quality, because they are costly to produce and maintain. These signals are reliable because only high-quality individuals can afford the associated costs, while lower-quality individuals would incur a disadvantage. Thus, signaling helps in mate selection or in deterring rivals, ensuring that the information conveyed is truthful and beneficial for the receiver's decision-making.

Professor: Let me give you an example from a study on peacocks. Male peacocks have elaborate, colorful tails, which are very heavy and make them slower and more visible to predators. This is a classic signal. In the study, researchers measured the number of eye spots on the tails. They found that females preferred males with more eye spots, but more importantly, males with more eye spots had better health and stronger immune systems. The tail is costly—it takes a lot of energy to grow and maintain, and it impairs movement. So only a healthy male can afford to produce and carry such a large tail. A sickly male would have a smaller, duller tail because the cost would be too high for him. Thus, the tail honestly signals the male's genetic quality, and females use this signal to choose the best mate.