translation.en: Some visitors came, using various behavioral change tricks like putting out a plate of food and a plate of shit and watching the flies go one to the other.
translation.zh: 一些人过来，用了各种行为改变技巧 比如拿出一盘食物和一盘粪便 让当地人观察苍蝇们从一盘飞向另一盘。