The author found that the rituals promoted economic life in terms of replacing production technology, controlling production power, expressing victory over nature and emphasizing the role of supernatural power in inducing fertility. For social life, they encouraged villagers to solve problems by themselves and promote social unity at the collective level. At the individual level, they were used to teat sicknesses and to ease the worries of villagers. In addition, the rituals were affected by socio-economic changes, with the changes being gradual in terms of relaxing practices, degradation, recurrence and less belief. Causes of these changes included a need to have more extravagant rituals in order to have more fun and to better appease spirits invited to participate. Others were economic needs, lack of sacrificial items, political change, production methods, and the influence of modern science.