 From the 1920s onward, the scientific study of religion became less concerned with grand unifying narratives, and focused more on particular religious traditions and beliefs. Anthropologists such as Edward Evans-Pritchard (1937) and Bronisław Malinowski (1925) no longer relied exclusively on second-hand reports (usually of poor quality and from distorted sources), but engaged in serious fieldwork. Their ethnographies indicated that cultural evolutionism was a defective theoretical framework and that religious beliefs were more diverse than was previously assumed. They argued that religious beliefs were not the result of ignorance of naturalistic mechanisms. For instance, Evans-Pritchard (1937) noted that the Azande were well aware that houses could collapse because termites ate away at their foundations, but they still appealed to witchcraft to explain why a particular house collapsed at a particular time. More recently, Cristine Legare et al. (2012) found that people in various cultures straightforwardly combine supernatural and natural explanations, for instance, South Africans are aware AIDS is caused by the HIV virus, but some also believe that the viral infection is ultimately caused by a witch.