Mental deficiency

Mental deficiency is the old term for mental retardation and is of historical interest only. It has fallen out of use because of its historical and negative connotations and no longer figures in the current literature.

Attempts to develop a classification and nomenclature of the different levels of intellectual deficiency led to a number of schemas and terms that built on common usage in various countries, but which were informed by the development of IQ tests

So for example one scheme categorised people into groups by IQ:


 * Borderline deficiency - (70-80)
 * Moron - (50-69)
 * Imbecile - (20-49)
 * Idiot - (below 20)

Other categorizations included


 * Feeblemindedness (Below 70 - North American : 50-69 - British)
 * Subnormal - (75-80)

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Papers

 * Google Scholar