Previous studies have reported that older people are more knowledgeable about nature than the younger generation. The relationship between people’s age and level of knowledge can be explained via two mechanisms: knowledge increases with age (wisdom of the elders), and opportunities to acquire knowledge decrease with successive generations (loss of experience). In this study, we examined the association between age and knowledge regarding the use of wild fruits among people living on Awaji Island in Japan. Analysis of the results revealed that the decline in knowledge among young people can be attributed to loss of experience. Furthermore, we found that the channels of knowledge transfer have changed between generations, earlier, children received it from their peers, but in recent years, it has been coming to them from older people and teachers.