托福口语 Task 3

The concept of 'signaling theory' in economics suggests that in situations of information asymmetry, one party may use observable signals to convey hidden qualities to another party. These signals are costly to fake, making them reliable indicators of underlying attributes. For instance, in the job market, employers cannot directly observe a candidate's productivity, so they rely on education credentials as a signal. The theory posits that individuals with higher ability are more likely to obtain such credentials because they find it easier to complete the required education, whereas lower-ability individuals would find the cost too high. Thus, the signal helps reduce uncertainty in decision-making.

Professor: Let me give you an example from the used car market. Suppose you want to buy a used car, but you can't tell if it's reliable or a lemon. The seller knows the car's history, but you don't. This is information asymmetry. Now, some sellers offer a warranty—say, a one-year free repair guarantee. This warranty acts as a signal. A seller with a reliable car is confident that few repairs will be needed, so offering a warranty is cheap for them. But a seller with a lemon knows repairs would be frequent and costly, so offering a warranty would be expensive. Therefore, only the seller with a good car will offer a warranty. As a buyer, when you see a warranty, you infer the car is reliable, even though you haven't inspected it. The warranty is costly to fake, so it effectively signals quality.