The study looked at how people value environmental resources in the Sanjiang plain. They used a method called contingent valuation to understand how much individuals are willing to pay to improve the environment. The researchers found that the distance between people and the environmental resources affects their willingness to pay. People living closer to the resources are more willing to pay for their protection and improvement. This is known as the Distance Decay Effect. By analyzing people's attitudes and perceptions towards environmental goods, the researchers were able to identify differences in willingness to pay based on where individuals live in relation to the resources.