The nuns from a convent in Bavaria in southern Germany were chosen so as to eliminate any outside influences that might falsify the results, psychologist and epidemiologist Horst Bickel told the Catholic press agency KNA on Wednesday.
The nuns were the perfect sample group, he explained, because they were one homogenous group who had lived together for decades in the same convent with similar conditions of daily life.
The results were telling.
Out of 442 nuns studied, 104 showed signs of dementia. Ninety-two of those had a low level of education, showing a correlation between education level when young and the development of cognitive difficulties in later life.
The study also showed that nuns who had been entrusted with positions of responsibility were less at risk of developing senility.
Bickel thanked the nuns for their participation. As for Sister Erharda Bauer, one of the leading nuns, she explained that the sisters had wanted to "help science, and therefore man."