A major obstacle to studying culture in nature is that, barring experimental introductions, we can never demonstrate convincingly that an animal we observe invents some new trick rather than simply applying a well-remembered but rarely practiced habit.
研究野生文化有个主要障碍,那就是:我们无法教人信服地证明,我们观察的野生动物发明了一个新技术,而不只是展现早已记住却很少实践的习惯,除非我们设法将新技术教会牠们。