Condition of limited mental development. In many countries since early Christian times it has been the object of the Church's special care. The degrees of feeblemindedness are commonly distinguished on the basis of a person's intelligence quotient as follows: idiocy, with a mental age up to three years and requiring constant supervision; imbecility, with a mental age up to seven years, having the ability to learn simple tasks but seldom reading or writing; and moronic state, with a mental age from eight to twelve years, and the ability to do sometimes even complex manual labor. Less than 10 per cent show any physical deformity. their moral responsibility depends on the mental age but especially on their religious training. It has been noted that mentally defective persons nevertheless show remarkable capacity for religious motivation and spiritual development. In ordinary usage, the technical terms for feeblemindedness are replaced with synonyms such as retardation or mentally handicapped.